HomeMy WebLinkAboutDraft CAO Amendments_250929_v1_Strikethrough_UnderlinePage 1
Revised 09/29/25
4-3-050 CRITICAL AREAS REGULATIONS:
4-3-050A PURPOSE
4-3-050B APPLICABILITY
4-3-050C EXEMPT, PROHIBITED AND NONCONFORMING ACTIVITIES
4-3-050D ADMINISTRATION AND INTERPRETATION
4-3-050E MAPS
4-3-050F SUBMITTAL REQUIREMENTS AND FEES
4-3-050G DEVELOPMENT STANDARDS
4-3-050H ALTERATIONS TO CRITICAL AREAS AND/OR BUFFERS – GENERAL REQUIREMENTS
4-3-050I ALTERATIONS TO CRITICAL AREAS BUFFERS
4-3-050J ALTERATIONS TO CRITICAL AREAS
4-3-050K VARIANCES
4-3-050L MITIGATION, MAINTENANCE AND MONITORING
4-3-050M APPEALS
4-3-050N UNAUTHORIZED ALTERATIONS AND ENFORCEMENT
4-3-050A PURPOSE:
The purposes of this Section are to:
1. Manage development activities to protect environmental quality, promote diversity of species, and habitat
within the City by regulating critical areas, including wetlands, aquifer protection areas, flsh and wildlife
habitat, frequently fiooded areas, and geologically hazardous areas as deflned by the Growth Management
Act and RMC 4-11.
2. Ensure that activities in or affecting critical areas do not threaten public safety, cause nuisances, or
destroy or degrade critical area functions and values;
3. Prevent the loss of critical area acreage and functions and strive for a net gain over present conditions
through restoration where feasible;
4. Assist or further the implementation of the policies of the Growth Management Act, the State
Environmental Policy Act, and the City Renton Comprehensive Plan;
5. Provide City officials with information to evaluate, approve, condition or deny public or private
development proposals with regard to critical area impacts;
6. Protect the public life, health, safety, welfare, and property by minimizing and managing the adverse
environmental impacts of development within and abutting critical areas;
7. Protect the public from:
a. Avoidable monetary losses due to maintenance and replacement of public facilities and utilities,
property damage, public mitigation of avoidable impacts, and public emergency rescue and relief
operations; and
b. Potential litigation on improper construction practices occurring in critical areas;
8. Reduce the potential for damage to life and property from abandoned coal mines, and return the land to
productive uses;
9. Maintain, to the extent practicable, a stable tax base by providing for the sound use and development of
areas of fiood hazard areas so as to minimize future fiood blight areas; and
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10. Protect riparian habitat and ecological processes in order to provide for bank and channel stability,
sustained water supply, fiood storage, recruitment of woody debris, leaf litter, nutrients, sediment and
pollutant flltering, shade, shelter, and other functions that are important to both flsh and wildlife.
4-3-050B APPLICABILITY:
1. Lands to Which These Regulations Apply and Non-regulated Lands: The following critical areas are
regulated by this Section. Multiple development standards may apply to a site feature based upon
overlapping critical area(s) and/or critical area classiflcations:
a. Flood hazard areas. Including fioodways and channel migration zones.
b. Geologic Hazards. Steep slopes (must have a minimum vertical rise of flfteen feet (15')), landslide
hazards, erosion hazards, seismic hazards, and/or coal mine hazards or on sites within flfty feet (50') of
steep slopes, landslide hazards, erosion hazards, seismic hazards, and/or coal mine hazards classifled
under RMC 4-3-050G5a which are located on abutting or adjacent sites.
c. Habitat Conservation Areas.
d. Streams and Lakes. All applicable requirements of this Section apply to Class F, Np, and Ns water
bodies, as deflned in subsection G7 of this Section or on sites within one hundred feet (100') of Class F,
Np, and Ns water bodies, except Type S water bodies, inventoried as “Shorelines of the State,” are not
subject to this Section, and are regulated in RMC 4-3-090, Shoreline Master Program Regulations, and
RMC 4-9-190, Shoreline Permits.
e. Wellhead Protection Areas.
f. Wetlands, Categories I, II, III, and IV or on sites within two hundred feet (200') of Category I, II, III, and IV
wetlands.
Wetlands created or restored as a part of a mitigation project are regulated wetlands. Regulated wetlands do
not include those artiflcial wetlands intentionally created from non-wetland sites, including, but not limited
to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment
facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990, that were
unintentionally created as a result of the construction of a road, street, or highway.
g. Sites Separated from Critical Areas, Nonregulated: As determined by the Administrator, these
regulations may not apply to development proposed on sites that are separated from critical areas by
pre-existing, intervening, and lawfully created structures, roads, or other substantial existing
improvements. For the purposes of this Section, the intervening lots/parcels, roads, or other substantial
improvements shall be found to:
i. Separate the subject upland property from the critical area due to their height or width; and
ii. Substantially prevent or impair delivery of most functions from the subject upland property to the
critical area. Such determination and evidence shall be included in the application flle. Public
notiflcation shall be given as follows:
(a) For applications that are not subject to notices of application pursuant to Chapter 4-8 RMC,
notice of the buffer determination shall be given by posting the site and notifying parties of record, if
any, in accordance with Chapter 4-8 RMC.
(b) For applications that are subject to notices of application, the buffer determination or request
for determination shall be included with notice of application. Upon determination, notiflcation of
parties of record, if any, shall be made.
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2. Activities to Which These Regulations Apply: The provisions of this Section shall apply to any regulated
activity that potentially affects a critical area or its buffer unless otherwise exempted by these regulations.
Where a regulated activity would be partly within and partly outside a critical area or its buffer, the entire
activity shall be reviewed pursuant to the requirements of this Section. Applicable activities are as follows:
a. Removing, excavating, disturbing, or dredging soil, sand, gravel, minerals, organic matter or materials
of any kind.
b. Dumping, discharging, or fllling with any material.
c. Draining, fiooding, or disturbing the water level or water table, or diverting or impeding water fiow.
d. Driving pilings or placing obstructions.
e. Constructing, substantially reconstructing, demolishing, or altering the size of any structure or
infrastructure.
f. Destroying or altering vegetation through clearing, grading, harvesting, shading, or planting vegetation
that would negatively affect the character of a critical area.
g. Changing, signiflcantly, water temperature, physical or chemical characteristics of water sources,
including quantity and pollutants by any activity.
h. Affecting, potentially, a critical area or buffer by any other activity not otherwise exempt from the
provisions of this Section as determined by the department.
4-3-050C EXEMPT, PROHIBITED AND NONCONFORMING ACTIVITIES:
1. Permit Required:
a. Development or Alteration: Prior to any development or alteration of a property containing a critical
area as deflned in subsection B of this Section, entitled Applicability, the owner or designee must obtain
a development permit, critical area permit, and/or letter of exemption. No separate critical area permit
is required for a development proposal for which requires development permits are required or
whichthat has received a letter of exemption.
b. Operating and Closure Permits – Wellhead Protection Areas: Wellhead Protection Areas operating
permit and closure permit requirements are contained in RMC 4-9-015, Aquifer Protection Areas
Permits.
2. Letter of Exemption:
a. Flood Hazard Areas, Geologically Hazardous Areas, Habitat Conservation Areas, Streams and
Lakes, Wellhead Protection Areas, Wetlands: Except in the case of public emergencies, all other
exemptions in this subsection C may require that a letter of exemption be obtained from the
Administrator prior to construction or initiation of activities.
b. Applicability of Requirements to Exempt Activities: Exempt activities provided with a letter of
exemption may intrude into the critical area or required buffer subject to any listed conditions or
requirements. Exempt activities do not need to comply with mitigation ratios of subsection J of this
Section unless required in exemption criteria.
c. Reports and Mitigation Plans Required: A critical area report, and/or enhancement or mitigation
plan shall be required pursuant to subsections F and L of this Section, unless otherwise waived by the
Administrator.
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d. Administrator Findings: In determining whether to issue a letter of exemption for activities listed in
this subsection C, the Administrator shall flnd that:
i. The activity is not prohibited by this or any other provision of the Renton Municipal Code or State
or Federal law or regulation;
ii. The activity will be conducted using best management practices as specifled by industry
standards or applicable Federal agencies or scientiflc principles;
iii. Impacts are minimized and, where applicable, disturbed areas are immediately restored;
iv. Where water body or buffer disturbance has occurred in accordance with an exemption during
construction or other activities, revegetation with native vegetation shall be required;
v. If a hazardous material, activity, and/or facility that is exempt pursuant to this Section has a
signiflcant or substantial potential to degrade groundwater quality, then the Administrator may
require compliance with the Wellhead Protection Area requirements of this Section otherwise
relevant to that hazardous material, activity, and/or facility. Such determinations will be based
upon site and/or chemical-speciflc data.
3. Exemptions – Critical Areas and Buffers: Exempt activities are listed in the following table. If an “X”
appears in a box, the listed exemption applies in the specifled critical area and required buffer. If an “X” does
not appear in a box, then the exemption does not apply in the particular critical area or required buffer.
Where utilized in the following table the term “restoration” means returning the subject area back to its
original state or better following the performance of the exempt activity. Activities taking place in critical
areas and their associated buffers and listed in the following table are exempt from the applicable provisions
of this Section, provided a letter of exemption has been issued. Whether the exempted activities are also
exempt from permits will be determined based upon application of chapters 4-8 and 4-9 RMC, or other
applicable sections of the Renton Municipal Code. All activities within shoreline jurisdiction are subject to
Shoreline Master Program Regulations in RMC 4-3-090 and 4-10-095.
EXEMPT ACTIVITIES – PERMITTED WITHIN CRITICAL AREAS AND ASSOCIATED BUFFERS
EXEMPT ACTIVITY Flood Hazard
Areas
Geologic
Hazard Area
Habitat
Conservation
Area
Streams and
Lakes: Type F,
Np, & Ns
Wellhead
Protection
Areas
Wetlands
a. Conservation, Enhancement, Education and Related Activities:
i. Natural
Resource/Habitat
Conservation or
Preservation2
X X X X X1 X
ii. Enhancement
activities as deflned in
chapter 4-11 RMC
X X X X X
iii. Approved
Restoration/Mitigation3 X X X X X1 X
b. Research and Site Investigation:
i. Nondestructive
Education and
Research
X X X X X1 X
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EXEMPT ACTIVITIES – PERMITTED WITHIN CRITICAL AREAS AND ASSOCIATED BUFFERS
EXEMPT ACTIVITY Flood Hazard
Areas
Geologic
Hazard Area
Habitat
Conservation
Area
Streams and
Lakes: Type F,
Np, & Ns
Wellhead
Protection
Areas
Wetlands
ii. Site Investigative
Work4 X X X X X1 X
c. Agricultural, Harvesting, Vegetation Management:
i. Harvesting Wild
Foods5 X X X X X1 X
ii. Existing/Ongoing
Agricultural Activities6 X X X X X
iii. Dangerous Trees7 X X X X8 X1 X8
d. Surface Water:
i. New Surface Water
Discharges9 X X X
ii. Modiflcation of
existing Regional
Stormwater Facilities10
X
iii. Flood Hazard Areas
Reduction11 X X
iv. Storm Drainage
Piping12 X
e. Roads, Parks, Public and Private Utilities18:
i. Relocation of Existing
Utilities out of Critical
Area and Buffer13
X X X X X1 X
ii. Maintenance,
Operation, and Repair
of existing Parks,
Trails, Roads,
Facilities, and Utilities,
and the Construction
of New Trails14
X X X X X X
iii. Utilities, Traffic
Control, Walkways,
Bikeways Within
Existing, Improved
Right-of-Way or
Easements15
X X X X
iv. Modiflcation of
Existing Utilities and
Streets by Ten Percent
(10%) or Less16
X X17 X17
f. Temporary Wetland Impacts:
i. Temporary Wetland
Impacts19 X X
g. Maintenance and Construction – Existing Uses and Facilities:
i. Remodeling,
Replacing, Removing X X X X
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EXEMPT ACTIVITIES – PERMITTED WITHIN CRITICAL AREAS AND ASSOCIATED BUFFERS
EXEMPT ACTIVITY Flood Hazard
Areas
Geologic
Hazard Area
Habitat
Conservation
Area
Streams and
Lakes: Type F,
Np, & Ns
Wellhead
Protection
Areas
Wetlands
Existing Structures,
Facilities, and
Improvements20
ii. Maintenance and
Repair – Any Existing
Public or Private Use21
X X X X
iii. Modiflcation of an
Existing Residential
StructureSingle
Family22
X X X X
iv. Existing Activities23 X X X X X
h. Emergency Activities:
i. Emergency
Activities24, 25, 26, 27 X X X X X1 X
i. Hazardous Materials:
i. Federal or State
Preemption28 X1
ii. Use of Materials
with No Risk29 X1
Footnotes:
1. If a hazardous material, activity, and/or facility that is exempt pursuant to this Section has a
signiflcant or substantial potential to degrade groundwater quality, then the Administrator may require
compliance with the Wellhead Protection Area requirements of this Section otherwise relevant to that
hazardous material activity and/or facility.
2. Conservation or preservation of soil, water, vegetation, flsh and other wildlife. Within shoreline
jurisdiction this includes watershed restoration projects as deflned in WAC 173-27-040(2)(o) or
projects to improve flsh or wildlife habitat or flsh passage approved by the Washington State
Department of Fish and Wildlife as described in WAC 173-27-040(2)(p).
3. Any critical area and/or buffer restoration or other mitigation activities which have been approved
by the City. Within shoreline jurisdiction this includes watershed restoration projects as deflned in
WAC 173-27-040(2)(o) or projects to improve flsh or wildlife habitat or flsh passage approved by the
Washington State Department of Fish and Wildlife as described in WAC 173-27-040(2)(p).
4. Site investigative work necessary for land use application submittals such as surveys, soil logs,
percolation tests and other related activities. Investigative work shall not disturb any more than flve
percent (5%) of the critical area and required buffer. In every case, impacts shall be minimized and
disturbed areas shall be immediately restored at a one-to-one (1:1) ratio. Within shoreline jurisdiction,
this includes the marking of property lines or corners on state-owned lands, when such marking does
not signiflcantly interfere with the normal public use of the surface water. Limitations on site
exploration and investigative activities are deflned in WAC 173-27-040(2)(m) for properties within
shoreline jurisdiction.
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5. The harvesting of wild foods in a manner that is not injurious to natural reproduction of such foods
and provided the harvesting does not require tilling of soil, planting of crops or alteration of the critical
area.
6. Existing and ongoing agricultural activities including farming, horticulture, aquaculture and/or
maintenance of existing irrigation systems. Activities on areas lying fallow as part of a conventional
rotational cycle are part of an ongoing operation; provided, that the agricultural activity must have
been conducted within the last flve (5) years. Activities that bring a critical area into agricultural use are
not part of an ongoing operation. Maintenance of existing legally installed irrigation, ditch and pipe
systems is allowed; new or expanded irrigation, ditch, outfall or other systems are not exempt. If it is
necessary to reduce the impacts of agricultural practices to critical areas, a farm management plan
may be required based on the King County Conservation District’s Farm Conservation and Practice
Standards, or other best management practices. Within shoreline jurisdiction practices normal or
necessary for farming are deflned in WAC 173-27-040(2)(e).
7. Removal of non-native invasive ground cover or weeds listed by King County Noxious Weed Board
or other government agency or dangerous trees, as deflned in chapter 4-11 RMC, which have been
approved by the City and certifled dangerous by a licensed landscape architect, or certifled arborist,
selection of whom to be approved by the City based on the type of information required.
8. Limited to cutting of dangerous trees; such hazardous trees shall be retained as large woody debris
in critical areas and/or associated buffers, where feasible.
9. New surface water discharges in the form of dispersion trenches, outfalls and bioswales are
allowed within the outer twenty flve percent (25%) of the buffer of a Category III or IV wetland only
provided that: the discharge meets the requirements of the Drainage (Surface Water) Standards (RMC
4-6-030); no other location is feasible; and will not degrade the functions or values of the wetland or
stream. Where differences exist between these regulations and RMC 4-6-030, these regulations will
take precedence.
10. Modiflcations to existing regional stormwater management facilities operated and maintained
under the direction of the City Surface Water Utility that are designed consistent with the current
version of the Washington State Department of Ecology Stormwater Management Manual or meeting
equivalent objectives.
11. Implementation of public fiood hazard areas reduction and public surface water projects, where
habitat enhancement and restoration at a one-to-one (1:1) ratio are provided, and appropriate Federal
and/or State authorization has been received.
12. Installation of new storm drainage lines in any geologic hazard area when a geotechnical report
clearly demonstrates that the installation would comply with the criteria listed in RMC 4-3-050.J.1 and
that the installation would be consistent with each of the purposes of the critical area regulations
listed in RMC 4-3-050.A. Also, to qualify for the exemption, the report must propose appropriate
mitigation for any potential impacts identifled in the report.
13. Relocation out of critical areas and required buffers of natural gas, cable, communication,
telephone and electric facilities, lines, pipes, mains, equipment and appurtenances (not including
substations), with an associated voltage of flfty- flve thousand (55,000) volts or less, only when
required by a local governmental agency, and with the approval of the City. Disturbed areas shall be
restored.
14. Normal and routine maintenance, operation and repair of existing parks, trails, streets, roads,
rights-of-way and associated appurtenances, facilities and utilities where no alteration or additional flll
materials will be placed other than the minimum alteration and/or flll needed to restore those facilities
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or to construct new trails to meet established safety standards. The use of heavy construction
equipment shall be limited to utilities and public agencies that require this type of equipment for
normal and routine maintenance and repair of existing utility structures and rights-of-way. In every
case, critical area and required buffer impacts shall be minimized and disturbed areas shall be
restored during and immediately after the use of construction equipment.
15. Within existing and improved public road rights-of-way or easements, installation, construction,
replacement, operation, overbuilding or alteration of all- natural gas, cable, communication,
telephone and electric facilities, lines, pipes, mains, equipment or appurtenances, traffic control
devices, illumination, walkways and bikeways. If activities exceed the existing improved area or the
public right-of-way, this exemption does not apply. Where applicable, restoration of disturbed areas
shall be completed. Within shoreline jurisdiction the exemption also applies to any project with a
certiflcation from the Governor pursuant to chapter 80.50 RCW.
16. Overbuilding (enlargement beyond existing project needs) or replacement of existing utility
systems and replacement and/or rehabilitation of existing streets, provided:
a. The work does not increase the footprint of the structure, line or street by more than ten
percent (10%) within the critical area and/or buffer areas, and occurs in the existing right-of-
way boundary or easement boundary.
b. Restoration shall be conducted where feasible. Compensation for impacts to buffers shall
include enhancement of the remaining buffer area along the impacted area where there is
enhancement opportunity. Restoration and enhancement of wetlands shall consider
Wetland Mitigation in Washington State, Part 1: Agency Policies and Guidance, Version 2
(Ecology Publication No. 21-06-003, April 2021) and future addenda.
c. The Administrator determines that, based on best judgment, a person would not: (i) be able
to meaningfully measure, detect, or evaluate insigniflcant effects; or (ii) expect discountable
effects to occur.
d. This exemption allows for ten percent (10%) maximum expansion total, life of the project.
After the ten percent (10%) expansion cap is reached, future improvements are subject to all
applicable provisions of this Section.
17. Exemption is not allowed in Category I wetlands.
18. Maintenance activities, including routine vegetation management and essential tree removal, and
removal of non-native invasive vegetation or weeds listed by the King County Noxious Weed Board or
other government agency, for public and private utilities, road rights-of-way and easements, and
parks.
19. Temporary disturbances of a wetland due to construction activities that do not include
permanent fllling may be permitted; provided, that there are no permanent adverse impacts to the
critical area or required buffer, and areas temporarily disturbed are restored at a one-to-one (1:1) ratio.
Category I wetlands and Category II forested wetlands shall be enhanced at a two-to-one (2:1) ratio in
addition to being restored consistent with Wetland Mitigation in Washington State, Part 1: Agency
Policies and Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021). For Habitat
Conservation Areas, this exemption applies only to Category I wetlands.
20. Remodeling, restoring, replacing or removing structures, facilities and other improvements in
existence or vested on the date this Section becomes effective and that do not meet the setback or
buffer requirements of this Section provided the work complies with the criteria in RMC 4-10-090.
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21. Normal and routine maintenance and repair of any existing public or private uses and facilities
where no alteration of the critical area and required buffer or additional flll materials will be placed.
The use of heavy construction equipment shall be limited to utilities and public agencies that require
this type of equipment for normal and routine maintenance and repair of existing utility or public
structures and rights-of-way. In every case, critical area and required buffer impacts shall be
minimized and disturbed areas shall be restored during and immediately after the use of construction
equipment. Normal maintenance and repair for structures within shoreline jurisdiction is deflned by
WAC 173-27-040(2)(b).
22. Additions and alterations of an existing residential structure single family residence and/or garage
(attached or detached); provided, that the addition/alteration does not increase the footprint of the
structure lying within the critical area or buffer; and provided, that no portion of the addition/alteration
occurs closer to the critical area or required buffers than the existing structure unless the structure or
addition can meet required buffers. Existing or rebuilt accessory structures associated with single
family dwelling residential structure and rebuilt with the same footprint such as fences, gazebos,
storage sheds, and play housesplayhouses are exempt from this Section. New accessory structures
may be allowed when associated with single-family dwellings a residential structure such as fences,
gazebos, storage sheds, play housesplayhouses and when built on and located in a previously legally
altered area.
23. Existing activities which have not been changed, expanded or altered, provided they comply with
the applicable requirements of chapter 4-10 RMC.
24. Emergency activities are those which are undertaken to correct emergencies that threaten the
public health, safety and welfare. An emergency means that an action must be undertaken
immediately or within a time frame too short to allow full compliance with this Section, to avoid an
immediate threat to public health or safety, to prevent an imminent danger to public or private
property, or to prevent an imminent threat of serious environmental degradation. Within shoreline
jurisdiction, emergency activities are deflned by WAC 173-27-040(2)(d).
25. Emergency tree and/or ground cover removal by any City department or agency and/or public or
private utility involving immediate danger to life or property, substantial flre hazards, or interruption of
services provided by a utility.
26. Emergency activities in Wellhead Protection Areas: Public interest emergency use, storage, and
handling of hazardous materials by governmental organizations.
27. Temporary emergency exemptions shall be used only in extreme cases and not to justify poor
planning by an agency or applicant. Issuance of an emergency permit by the City does not preclude the
necessity to obtain necessary approvals from appropriate Federal and State authorities.
Notwithstanding the provisions of this Section or any other City laws to the contrary, the Administrator
may issue a temporary emergency exemption letter if the action meets the requirements:
a. An unacceptable threat to life or severe loss of property will occur if an emergency permit is
not granted;
b. The anticipated threat or loss may occur before a permit can be issued or modifled under the
procedures otherwise required by this Section and other applicable laws;
c. Any emergency exemption letter granted shall incorporate, to the greatest extent practicable
and feasible but not inconsistent with the emergency situation, the standards and criteria
required for nonemergency activities under this Section.
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d. The emergency exemption shall be consistent with the following procedural and time
requirements:
i. The emergency shall be limited in duration to the time required to complete the
authorized emergency activity; provided, that no emergency permit be granted for a
period exceeding ninety (90) days except as specifled in RMC 4-3-050C.
ii. Any critical area altered as a result of the emergency activity must be restored within the
ninety (90) day period, except that if more than ninety (90) days from the issuance of the
emergency permit is required to complete restoration, the emergency permit may be
extended to complete this restoration. For the purposes of this subsection,
“restoration” means returning the affected area to its state prior to the performance of
the emergency activity.
iii. Notice of the issuance of the emergency permit and request for public comments shall
be posted at the affected site(s) and City Hall no later than ten (10) days after the
issuance of the emergency permit. If signiflcant comments are received, the City may
reconsider the permit.
iv. Expiration of Exemption Authorization: The emergency exemption authorization may be
terminated at any time without process upon a determination by the Administrator that
the action was not or is no longer necessary to protect human health or the
environment.
28. Cleanups, monitoring and/or studies undertaken under supervision of the Washington
Department of Ecology or the U.S. Environmental Protection Agency.
29. Use, storage, and handling of speciflc hazardous materials that do not present a risk to the
aquifer as determined and listed by the Department.
(Ord. 5976, 8-3-2020; Ord. 6128 (Att. E), 12-11-2023)
4. Exemptions – In Buffers Only: The activities listed in the following table are allowed within critical area
buffers, and are exempt from the applicable provisions of this Section, provided a letter of exemption has
been issued pursuant to this subsection C. If an “X” appears in a box, the listed exemption applies in the
specifled buffer. If an “X” does not appear in a box, then the exemption does not apply in the required buffer.
Whether the exempted activities are also exempt from permits will be determined based upon application of
chapters 4-8 and 4-9 RMC, or other applicable sections of the Renton Municipal Code. All activities within
shoreline jurisdiction are subject to Shoreline Master Program Regulations in RMC 4-3-090 and 4-10-095.
EXEMPTIONS WITHIN CRITICAL AREA BUFFERS
EXEMPT
ACTIVITY
Flood Hazard
Areas
Geologic Hazard
Area
Habitat
Conservation
Areas
Streams and
Lakes: Types F,
Np, & Ns
Wellhead
Protection Areas Wetlands
a. Activities in Critical Area Buffers:
i. Trails and Open
Space1 X X X X
ii. Stormwater
Treatment and
Flow Control
X
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EXEMPTIONS WITHIN CRITICAL AREA BUFFERS
EXEMPT
ACTIVITY
Flood Hazard
Areas
Geologic Hazard
Area
Habitat
Conservation
Areas
Streams and
Lakes: Types F,
Np, & Ns
Wellhead
Protection Areas Wetlands
Facilities in
Buffer2
iii. Stormwater
Conveyance in
Buffer3
X X X
Footnotes:
1. Walkways and trails, and associated open space in critical area buffers located on public property, or
where easements or agreements have been granted for such purposes on private property. All of the
following criteria shall be met:
a. The trail, walkway, and associated open space shall be consistent with the Parks, Recreation, and
Natural Areas Plan. The City may allow private trails as part of the approval of a site plan, subdivision or
other land use permit approvals.
b. Trails and walkways shall be located in the outer twenty flve percent (25%) of the buffer, i.e., the
portion of the buffer that is farther away from the critical area. Exceptions to this requirement may be
made for:
i. Trail segments connecting to existing trails where an alternate alignment is not practical.
ii. Public access points to water bodies spaced periodically along the trail.
c. Enhancement of the buffer area is required where trails are located in the buffer. Where
enhancement of the buffer area abutting a trail is not feasible due to existing high- quality vegetation,
additional buffer area or other mitigation may be required consistent with Wetland Mitigation in
Washington State, Part 1: Agency Policies and Guidance, Version 2 (Ecology Publication No. 21-06-003,
April 2021).
d. Trail widths shall be a maximum width of twelve feet (12'). Trails shall be constructed of permeable
materials which that protect water quality, allow adequate surface water and ground water movements,
do not contribute to erosion, are located where they do not disturb nesting, breeding, and rearing areas,
and designed to avoid or reduce the removal of trees. Impervious materials may be allowed if pavement
is required for handicappedADA or emergency access, or for safety, or the trail is a designated
nonmotorized transportation route or makes a connection to an already dedicated trail, or the materials
reduces the potential for other environmental impacts.
e. Any crossing over a stream or wetland shall be generally perpendicular to the critical area and shall
be accomplished by bridging or other technique designed to minimize critical area disturbance. It shall
also be the minimum width necessary to accommodate the intended function or objective.
2. Stormwater management facilities shall not be built within a critical area buffer except as allowed in
Reference 5, Wetlands Protection Guidelines of the City’s Surface Water Design Manual and shall require
buffer enhancement or buffer averaging when they are sited in areas of forest vegetation, provided the
standard buffer zone area associated with the critical area classiflcation is retained pursuant to RMC 4-3-
050G2, and is sited to reduce impacts between the critical area and surrounding activities.
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3. Necessary conveyance systems including stormwater dispersion outfall systems designed to minimize
impacts to the buffer and critical area, where the site topography requires their location within the buffer to
allow hydraulic function, provided the standard buffer zone area associated with the critical area
classiflcation is retained pursuant to RMC 4-3-050G2, and is sited to reduce impacts between the critical
area and surrounding activities.
4. WAC 173-27-040(2)(g) deflnes and identifles the limitations on the construction of a single family home
and appurtenances. Single family residences and appurtenances must be located landward of the ordinary
high- water mark and the perimeter of a wetland. Based on the results of a critical area report, and/or
enhancement or mitigation plan, the City shall condition development to require buffer enhancement or
buffer averaging, site design that reduces impacts between the critical area and surrounding activities, and a
building setback.
(Ord. 5976, 8-3-2020)
5. Prohibited Activities: Prohibited activities are identifled below for each critical area governed by this
Section. No action shall be taken by any person, company, agency, or applicant which results in any
alteration of a critical area except as consistent with the purpose, objectives, and requirements of this
Section.
a. Floodways: Encroachments, including flll, new construction, substantial improvements, and
construction or reconstruction of residential structures is prohibited within designated fioodways,
unless it meets the provisions of subsection G4e of this Section, Additional Restrictions within
Floodways.
b. Streams/Lakes and Wetlands: Grazing of animals is not allowed within a stream, lake, wetland or
their associated buffers.
c. Wellhead Protection Areas:
i. All Wellhead Protection Areas – Pesticides and Fertilizers: The application of hazardous
materials such as pesticides or fertilizers containing nitrates within one hundred feet (100') of a well
or two hundred feet (200') of a spring.
ii. Zone 1, as identifled in subsection G8 of this Section:
(a) Changes in land use and types of new facilities in which any of the following will be on the
premises:
(1) More than flve hundred (500) gallons of hazardous material;
(2) More than one hundred flfty (150) gallons of hazardous material in containers that are
opened and handled;
(3) Containers exceeding flve (5) gallons in size; or
(4) Tetrachloroethylene (e.g., dry-cleaning fiuid);
(b) Surface impoundments (as deflned in Chapters 173-303 and 173-304 WAC);
(c) Hazardous waste treatment, storage, and disposal facilities;
(d) All types of landfllls, including solid waste landfllls;
(e) Transfer stations;
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(f) Septic systems;
(g) Recycling facilities that handle hazardous materials;
(h) Underground hazardous material storage and/or distribution facilities;
(i) New heating systems using fuel oil except for commercial uses when the source of fuel oil is
an existing above-ground waste oil storage tank;
(j) Petroleum product pipelines;
(k) Hazardous materials use on the site in quantities greater than that allowed for new facilities
as provided in subsection C5ciia of this Section, changes in land use and types of new facilities,
of this subsection, once a facility is closed, relocated, or the use of hazardous materials is
terminated, reinstatement of the use of hazardous materials shall be prohibited;
(l) Facility closure, sale, transfer or temporary or permanent abandonment in a Wellhead
Protection Area without complying with the requirements of RMC 4-9-015F, Closure Permit, and
permit conditions of this Section; and
(m) Facility changes in operations that increase the aggregate quantity of hazardous materials
stored, handled, treated, used, or produced with the following exception: An increase in the
quantity of hazardous materials is allowed up to the amount allowed for a new facility as
provided by subsection C5ciia of this Section, changes in land use and types of new facilities, of
this Section.
iii. Zone 2, as identifled in subsection G8 of this Section:
(a) Surface impoundments (as deflned in Chapters 173-303 and 173-304 WAC);
(b) Recycling facilities that handle hazardous materials;
(c) Hazardous waste treatment, storage, and disposal facilities;
(d) Solid waste landfllls;
(e) Transfer stations;
(f) New heating systems using fuel oil stored in underground storage tanks; and
(g) Petroleum product pipelines.
iv. Zone 1 Modifled, as identifled in subsection G8 of this Section: The prohibitions of Zone 1
Modifled are the same as Zone 1 with the exceptions as follows:
(a) Hazardous Materials Inventory: Existing facilities are not subject to the flve hundred (500)
gallons maximum hazardous material quantity limitation in Zone 1 and therefore don’t have to
reduce inventory or relocate. Proposed facilities are subject to the maximum quantity.
(b) Septic Tanks: Existing septic tanks are allowed to remain, and new septic tanks are allowed
if City sewers are not available.
(c) Surface Water Management: Inflltration of runoff is allowed, and pipe materials are not
subject to Zone 1 speciflcations.
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(d) Site Improvements: An existing facility that was in compliance with improvements required
at the installation of the facility is not subject to new site improvements (groundwater
monitoring, paving, runoff control, etc.).
6. Nonconforming Activities or Structures: Regulated activities legally in existence prior to the passage of
this Section, but which are not in conformity with the provisions of this Section, are subject to the provisions
of RMC 4-10-090, Critical Areas Regulations – Nonconforming Activities and Structures.
4-3-050D ADMINISTRATION AND INTERPRETATION:
1. Interpretation: The Administrator shall have the power to render interpretations of this Section and to
adopt and enforce rules and regulations supplemental to this Section as he/she may deem necessary in
order to clarify the application of the provisions of this code. Such interpretations, rules and regulations shall
be in conformity with the intent and purpose of this Section. Provisions contained within this Section are
considered the minimum requirements and will not limit or repeal other provisions under State statute.
a. Relationship to Other Agencies and Regulations:
i. These critical areas regulations shall be in addition to zoning and other regulations adopted by the
City. Compliance with other regulations does not exempt the applicant from critical areas
regulations. In the event of any confiict between these regulations and any other City regulations,
those regulations which provide the greater protection to critical areas shall apply.
ii. Any individual critical area adjoined by another type of critical area shall have the buffer and meet
the requirements that provide the most protection to the critical areas involved. When any provision
of this Section or any existing regulation, or easement, covenant, or deed restriction granted to any
governmental body confiicts with this Section, that which provides more protection to the critical
areas shall apply.
iii. Compliance with the provisions of this Section does not constitute compliance with other
Federal, State, and local regulations and permit requirements that may be required (for example,
shoreline substantial development or conditional use permits, shoreline variances, the Washington
State Department of Fish and Wildlife hydraulic project approval (HPA), Army Corps of Engineers
Section 404 permits, Department of Ecology 401 Water Quality Certiflcations and National Pollution
Discharge Elimination System (NPDES) permits). The applicant is responsible for complying with
these requirements, apart from the process established in this Section.
2. Duties of Administrator: The Administrator shall have the power and authority to issue decisions relative
to and enforce the provisions of this Section.
a. Compliance: The City shall not grant any approval or permit any regulated activity in a critical area or
associated buffer prior to fulfllling the requirements of this Section.
b. Review: The Administrator shall review all development permits to determine that the requirements
of this Section have been satisfled.
c. Finding of Conformance Required: Conformance with these critical area regulations shall be a
flnding in any approval of a development permit or aquifer protection area permit, and such flnding shall
be documented in writing in the project flle.
3. Flood Hazard Areas:
a. Designation of the Floodplain Administrator: The Administrator is hereby appointed to administer,
implement, and enforce the provisions of this Section by granting or denying development permits in
accordance with its provisions. The Floodplain Administrator may delegate authority to implement these
provisions.
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b. Enforcement: All development within special fiood hazard areas and channel migration zones is
subject to the terms of this Section and other applicable regulations. The standards of this Section are
not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions.
However, where the standards of this Section and any other applicable regulation, easement, covenant,
or deed restriction confiict or overlap, whichever imposes the more stringent restrictions shall prevail.
These regulations, and the various parts thereof, are hereby declared to be severable. Should any
standard of this Section be declared by the courts to be unconstitutional or invalid, such decision shall
not affect the validity of this Section as a whole, or any portion thereof, other than the section so
declared to be unconstitutional or invalid.
c. Basis for Establishing the Areas of Special Flood Hazard: The special fiood hazard areas identifled
by the Federal Insurance Administrator in a scientiflc and engineering report entitled “The Flood
Insurance Study (FIS) for King County, Washington and Incorporated Areas” dated August 19, 2020, and
any revisions thereto, with accompanying Flood Insurance Rate Maps (FIRMs), and any revisions thereto,
are hereby adopted by reference and declared to be a part of this Section. The FIS and the FIRM are on
flle at City of Renton, 1055 South Grady Way, Renton, WA 98057. The best available information for fiood
hazard area identiflcation as outlined in subsection D3f of this Section shall be the basis for regulation
until a new FIRM is issued that incorporates data utilized under subsection D3f of this Section.
ed. Information to be Provided by Applicant: The applicant shall provide the Administrator the
following information:
i. The actual elevation, in relation to mean sea level, the North American Vertical Datum of 1988
(NAVD 88), of the lowest fioor (including basement) of all new or substantially improved structures,
and whether or not the structure contains a basement where base fiood elevation data is provided
through the fiood insurance study or required.
ii. For all new or substantially improved fiood proofed structures:
(a) The applicant shall verify and have recorded the actual elevation in relation to mean sea
level, the North American Vertical Datum of 1988 (NAVD 88); and
(b) Flood elevation certiflcates shall be submitted by an applicant to the Development Services
Division prior to the building’s flnished fioor construction. Finished fioor elevation should be
verifled by a preconstruction elevation certiflcate at the time of construction of a substantial
structural element of the flnished fioor (i.e., foundation form for the concrete fioor). An as-built
elevation certiflcate will be provided prior to issuance of flnal occupancy.
iii. Where a structure is to be fiood proofed, certiflcation by a registered professional engineer or
architect that the fiood prooflng methods for any nonresidential structure meet fiood prooflng
criteria in subsection G4diii(b) of this Section;
iv. Description of the extent to which a watercourse will be altered or relocated as a result of
proposed development;
v. Where a structure is proposed in a V, V1-30, or VE zone, a V-zone design certiflcate;
vi. Where development is proposed in a fioodway, an engineering analysis indicating no rise of the
Base Flood Elevation; and
vii. Any other such information that may be reasonably required by the Floodplain Administrator in
order to review the application.
ef. Information to be Obtained and Maintained:
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i. Where base fiood elevation data is provided through the FIS, FIRM, or required as in subsection
D3f of this Section, obtain and maintain a record of the actual (as-built) elevation (in relation to
mean sea level) of the lowest fioor (including basement) of all new or substantially improved
structures, and whether or not the structure contains a basement.
ii. For all new or substantially improved fiood proofed nonresidential structures where base fiood
elevation data is provided through the FIS, FIRM, or as required in subsection D3f of this Section:
(a) Obtain and maintain a record of the elevation (in relation to mean sea level) to which the
structure was fiood proofed.
(b) Maintain the fiood prooflng certiflcations required in subsection G4diii of this Section.
iii. Certiflcation required by subsection G4ei of this Section.
iv. Records of all variance actions, including justiflcation for their issuance.
v. Improvement and damage calculations.
vi. Maintain for public inspection all records pertaining to the provisions of this Section.
fg. Use of Other Base Flood Data (in A and V Zones): When base fiood elevation data has not been
provided (in A or V zones) in accordance with subsection D3c of this Section, Basis for Establishing the
Areas of Special Flood Hazard, the Floodplain Administrator shall obtain, review, and reasonably utilize
any base fiood elevation and fioodway data available from a federal, state, or other source, in order to
administer subsection G4d of this Section, Speciflc Standards, and subsection G4e of this Section,
Additional Restrictions within Floodways. (Ord. 5977, 8-10-2020)
g. Basis for Establishing the Channel Migration Zone: A channel migration zone for the Cedar River has
been identifled and mapped by King County in a report entitled Cedar River Channel Migration Study,
dated April 2015.The study shall be the basis for regulation until the study or portions thereof are
updated and accepted by the City, or unless the City approves a mapping change pursuant to RMC 4-3-
050.E.3.c, Channel Migration Zone Determination.
viii. At the request of a property owner or on its own initiative, the department may reassess and
adjust the boundary of a completed CMZ map within a smaller portion of the full CMZ study length
as follows:
1. A property owner may submit a critical area study to the department supporting the property
owner’s request for a site-speciflc reassessment of the CMZ boundary. The critical area study shall
be conducted using channel migration mapping methods and criteria specifled in King County’s
Designation, Classiflcation and Mapping of Channel Migration Zones Appendix A: Preparation of
Channel Migration Zone (CMZ) Study and Map.
2. The department may reassess and adjust the boundary of CMZ or its component hazard areas if it
determines that the conditions within a speciflc portion of an overall CMZ study area have changed
to the extent that the existing mapped CMZ boundary is no longer accurate. The reassessment and
adjustment shall be made using mapping methods and criteria specifled in King County’s
Designation, Classiflcation and Mapping of Channel Migration Zones Appendix A: Preparation of
Channel Migration Zone (CMZ) Study and Map.
3. If the department approves an adjustment to an existing CMZ map under subsection vii.1 or vii.2
of this section, the adjustment will be documented by City of Renton staff in a letter and annotated
portion of the adjusted CMZ map.
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4. Wellhead Protection Areas:
a. Annual Inspections: All permitted facilities in a Wellhead Protection Area will be subject to a
minimum of one inspection per year by a Department inspector.
b. Potential to Degrade Groundwater – Zone 2:
i. Potential for Impacts Equal to Facility in Zone 1: If the Administrator determines that an existing
or proposed facility located in Zone 2 of a Wellhead Protection Area has a potential to degrade
groundwater quality which equals or exceeds that of a permitted facility in Zone 1, then the
Administrator may require that facility to fully comply with requirements for Zone 1 contained in
RMC 4-3-050C5c and 4-3-050G8.
ii. Criteria: Criteria used to make the determination in this subsection D4 shall include but not be
limited to the present and past activities conducted at the facility; types and quantities of
hazardous materials stored, handled, treated, used or produced; the potential for the activities or
hazardous materials to degrade groundwater quality; history of spills at the site, and presence of
contamination on site.
c. Finding of Conformance Required – Wellhead Protection Areas: No changes in land use shall be
allowed nor shall permits for development be issued if the Department flnds that the proposed land use,
activity, or business is likely to impact the long-term, short-term or cumulative quality of the aquifer. The
flnding shall be based on the present or past activities conducted at the site; hazardous materials that
will be stored, handled, treated, used or produced; and the potential for the land use, activity, or
business to degrade groundwater quality.
5. Review Authority: The Administrator shall have the authority to interpret, apply, and enforce this Section
to accomplish the stated purpose. Based upon site-speciflc review and analysis, the City may withhold,
condition, or deny development permits or activity approvals to ensure that the proposed action is consistent
with this Section.
a. General: The Administrator is authorized to make the following administrative allowances and
determinations:
i. Issue a critical areas permit for proposals not otherwise requiring a development permit.
ii. Issue written letters of exemption.
iii. Allow temporary emergency exemptions.
iv. Interpret critical areas regulations.
v. Approve the use of alternates in accordance with RMC 4-9-250E.
vi. Waive report content or submittal requirements provided criteria to waive studies are met.
vii. Grant administrative variances to those specifled code sections listed in RMC 4-9-250B.
viii. Require tests for proof of compliance.
ix. Grant modiflcations pursuant to RMC 4-9-250D.
b. Conditions of Approval: The Administrator is authorized, through conditions of approval, to modify
the proposal, including, but not limited to, construction techniques, design, drainage, project
size/conflguration, or seasonal constraints on development. Upon review of a special study, the
development permit shall be conditioned to mitigate adverse environmental impacts and to assure that
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the development can be safely accommodated on the site and is consistent with the purposes of this
Section. A mitigation plan may be required consistent with subsection L1 of this Section.
c. Geologically Hazardous Areas, Habitat Conservation Areas, Streams and Lakes, and Wetlands:
The Administrator is authorized, pursuant to subsection H of this Section, entitled Alterations To Critical
Areas And/Or Buffers – General Requirements, to make the following administrative allowances and
determinations:
i. Geologically Hazardous Areas:
(a) Waive independent review of geotechnical reports.
(b) Increase or decrease required buffer for very high landslide hazard areas.
(c) Grant a modiflcation for created slopes.
ii. Streams and Lakes:
(a) Approve proposals for buffer width reductions.
(b) Approve proposals for buffer width averaging.
iii. Wellhead Protection Areas:
(a) Issue operating and closure permits.
(b) Determine pipeline requirements.
(c) Determine if Zone 1 requirements should apply in Zone 2 of a Wellhead Protection Area.
iv. Wetlands:
(a) Determine whether wetlands are unregulated.
(b) Extend the valid period of a wetland delineation.
(c) Approve proposals for buffer width reductions of up to twenty flve percent (25%).
(d) Approve proposals for buffer width averaging.
(e) Authorize other category level for created or restored wetlands.
(f) Waive requirements of this Section upon determination that all impacts on wetlands would be
mitigated as part of an approved area-wide wetlands plan that, when taken as a whole over an
approved schedule or staging of plan implementation, will meet or exceed the requirements of
this Section.
4-3-050E MAPS:
1. Maps Show Approximate Location of Critical Areas: The approximate location and extent of critical
areas within the City are shown on the critical areas inventory maps. The City supports a website, Maps and
GIS Data, which supports mapping applications, a map gallery, and downloadable GIS data. These maps
shall be used for informational purposes and as a general guide only, for the assistance of property owners
and other interested parties; the boundaries and locations shown are generalized. The actual presence or
absence, type, extent, boundaries, and classiflcation of critical areas on a speciflc site shall be identifled in
the fleld by a qualifled consultant and conflrmed by the Department, according to the procedures,
deflnitions, and criteria established by this Section. In the event of any confiict between the critical area
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location or designation shown on the City’s maps and the criteria or standards of this Section, the criteria
and standards shall prevail.
2. Map Updates: The Department updates critical area maps based on critical area reports prepared for
permit applications.
3. Flood Hazard Areas:
a. Basic Map and Documentation Identifying Hazards: Flood hazard areas are identifled pursuant to
RMC 4-3-050.D.3.c, Basis for Establishing the Areas of Special Flood Hazard, by the Federal Insurance
Administration in a scientiflc and engineering report entitled the Flood Insurance Study for the City of
Renton, dated September 29, 1989, and any subsequent revision, with accompanying fiood insurance
maps which are hereby adopted by reference and declared to be a part of this Section. The fiood
insurance study is on flle at the Public Works Department.
b. When Federal Insurance Study is Not Available: The Applicant shall obtain, for City review, and
reasonably utilization any base fiood elevation and fioodway data available from a Federal, State or
other source, in the following instances:
i. To administer subsection G of this Section when base fiood elevation data has not been provided
in accordance with this subsection E.
ii. To identify fiood hazard areas that will be regulated; until a new Flood Insurance Rate Map is
issued which incorporates the data utilized under subsection D of this Section.
4. Steep Slope Delineation Procedure: The boundaries of a regulated steep sensitive or protected slope are
determined to be in the location identifled on the City of Renton’s COR Maps, the City’s online interactive
mapping application available through the City’s website. An applicant’s qualifled professional may
substitute boundaries independently derived from survey data for the City’s consideration in determining the
boundaries of sensitive or protected steep slopes. All topographic maps shall utilize two- foot (2') contour
intervals, or the standard utilized in the City of Renton Steep Slope Atlas.
5. Streams and Lakes: Water class shall be determined in accordance with subsection G7a of this Section.
a. Reclassiflcation: The reclassiflcation of a water body to a lower class (i.e., F to Np, or Np to Ns, etc.)
requires Administrator acceptance of a stream or lake study, followed by an administrative legislative
amendment to the map in this subsection E prior to its effect. The reclassiflcation of a water body to a
higher class (i.e., Ns to Np, Np to F, or F to S) requires either: Administrator acceptance of a stream or
lake study or consultation with the Washington Department of Fish and Wildlife, followed by an
administrative legislative amendment to the map in this Section.
b. Salmonid Migration Barriers: For the purposes of classifying or reclassifying water bodies, features
determined by the Administrator to be salmonid migration barriers pursuant to the deflnition in RMC 4-
11-190 shall be mapped. The Administrator shall prepare and update the map as appropriate.
6. Wetlands: Categorization of wetlands shall be determined in accordance with subsection G9 of this
Section, and also refer to the City of Renton Wetland and Stream Corridors Critical Areas Inventory depicted
on the City of Renton’s COR Maps, the City’s online interactive mapping application available through the
City’s website.
4-3-050F SUBMITTAL REQUIREMENTS AND FEES:
1. Preapplication Consultation: Any person intending to develop properties known or suspected to have
critical areas present is strongly encouraged to meet with the appropriate City department representative
during the earliest possible stages of project planning before major commitments have been made to a
particular land use and/or project design. Effort put into a preapplication consultation and planning will help
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applicants create projects which will be more quickly and easily processed due to a better understanding on
the part of applicants of regulatory requirements.
2. Plans and Studies Required: When an application is submitted for any building permit or land use review
and/or to obtain approval of a use, development or construction, the location of the critical areas and buffers
on the site shall be indicated on the plans submitted based upon an inventory provided by a qualifled
specialist.
a. Geologically Hazardous Areas:
i. Whenever a proposed development requires a development permit and a geologic hazard is
present on the site of the proposed development or on abutting or adjacent sites within flfty feet
(50') of the subject site, geotechnical studies by licensed professionals, such as a geotechnical
engineer and/or engineering geologist, shall be required. Speciflcally, geotechnical studies are
required for developments proposed on sites with any of the following geologically hazardous
areas:
(a) Sensitive and protected slopes;
(b) Medium, high, or very high landslide hazards;
(c) High erosion hazards;
(d) High seismic hazards;
(e) Medium or high coal mine hazards.
ii. The required studies shall demonstrate the following review criteria can be met:
(a) The proposal will not increase the threat of the geological hazard to adjacent or abutting
properties beyond pre-development conditions; and
(b) The proposal will not adversely impact other critical areas; and
(c) The development can be safely accommodated on the site.
iii. A mitigation plan may be required consistent with subsection L of this Section.
iv. Sensitive Slopes – Medium, High and Very High Landslide Hazards – High Erosion Hazards:
Development applications shall submit erosion control plans consistent with chapter 4-8 RMC,
Permits – General and Appeals.
v. Coal Mine Hazards:
(a) Medium Hazard – Report Required: Reports consistent with chapter 4-8 RMC, Permits –
General and Appeals, shall be prepared for development proposed within medium coal mine
hazard areas and for development proposed within two hundred feet (200') of a medium coal
mine hazard area.
(b) High Hazard – Report Required: Reports consistent with chapter 4-8 RMC, Permits –
General and Appeals, shall be prepared for development proposed within high coal mine hazard
areas and for development proposed within flve hundred feet (500') of a high coal mine hazard
area.
b. Habitat Conservation Areas: Based upon subsection G6 of this Section, Habitat Conservation Areas,
the City shall require a habitat/wildlife assessment for activities that are located within or abutting a
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critical habitat, deflned in RMC 4-11-030, or that are adjacent to a critical habitat, and have the potential
to signiflcantly impact a critical habitat. The assessment shall determine the extent, function and value
of the critical habitat and potential for impacts and mitigation consistent with report requirements in
RMC 4-8-120D.
c. Streams and Lakes: The applicant shall be required to conduct a stream or lake study pursuant to
RMC 4-8-120 if a site contains a water body or buffer area and changes to buffer requirements or
alterations of the water body or its associated buffer are proposed, either administratively or via a
variance request. A stream or lake study is also required when the project area is within one hundred
feet (100') of a water body even if the water body is not located on the subject property.
d. Wellhead Protection Areas: The City may require an applicant to prepare a hydrogeologic study if the
proposal has the potential to signiflcantly impact groundwater quantity or quality, and sufficient
information is not readily available. Such a report shall be prepared by a qualifled professional at the
applicant’s expense. Report content requirements may be specifled by the City in accordance with State
or Federal guidelines or tailored to the particular development application. Peer review of the
applicant’s report may be required in accordance with this subsection F.
e. Wetlands:
i. Wetland Categorization: The applicant shall be required to conduct a study to determine the
categorization of the wetland if the subject property or project area is within two hundred feet (200')
of a wetland even if the wetland is not located on the subject property, but it is determined that
alterations of the subject property are likely to impact the wetland in question or its buffer. If there is
a potential Category I or II wetland within three hundred feet (300') of a proposal, the City may
require an applicant to conduct a study even if the wetland is not located on the subject property,
but it is determined that alterations of the subject property are likely to impact the wetland in
question or its buffer.
ii. Wetland Delineation: A wetland delineation using the methods identifled in the approved
federal delineation manual and applicable regional supplement, as required by WAC 173-22-035, is
required for any portion of a wetland or its buffer on the subject property that will be impacted by
the permitted activities.
iii. Wetland Assessment: The applicant shall prepare a wetland assessment pursuant to RMC 4-8-
120D23a through j.
f. Period of Validity: Studies submitted and reviewed are valid for flve (5) years from date of study
completion unless the Administrator determines that conditions have changed signiflcantly. The
Administrator may extend the period of validity, provided on-site conditions have not changed.
3. Testing Authorized:
a. Pipeline Requirements – Zone 1, As Identifled in Subsection G8 of This Section: If the Department
has reason to believe that the operation or proposed operation of an existing non-potable water pipeline,
deflned in RMC 4-11-160, in Zone 1 of a Wellhead Protection Area, may degrade groundwater quality, the
Department may require leakage testing of the existing pipeline in accordance with subsection G of this
Section; and installation, sampling, and sample analysis of monitoring wells. Routine leakage testing of
existing pipelines in Zone 1 may be required by the Department. Criteria for this determination are
specifled in subsection D of this Section.
Should pipeline leakage testing reveal any leakage at any level, then the Department shall require
immediate repairs to the pipeline to the satisfaction of the Department such that no inflltration of water
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into the pipeline or exflltration of substances conveyed in the pipeline shall occur. Any repairs which are
made shall be tested for leakage pursuant to subsection G of this Section.
b. Pipeline Requirements – Zone 2, As Identifled in Subsection G8 of This Section: If the Department
has reason to believe that the operation or proposed operation of an existing pipeline in Zone 2 of a
Wellhead Protection Area may degrade groundwater quality, the Department may require leakage
testing in accordance with subsection G of this Section; installation, sampling, and sample analysis of
groundwater monitoring wells; repair of the pipeline to the satisfaction of the Department such that
degradation of groundwater quality is minimized or eliminated. Criteria for this determination are
specifled under subsection D of this Section.
4. Submittal Requirements: In order to be accepted for review, studies shall include all information as
required in chapter 4-8 RMC.
5. Fees: See the currently adopted City of Renton Fee Schedule brochure available at the City’s website or in
the City Clerk’s Office.
6. Independent Secondary Review: The City may require independent review of an applicant’s report as
follows:
a. All Critical Areas: When appropriate due to the type of critical areas, habitat, or species present,
project area conditions, project scope, or potential for negative impacts to critical areas, or lack of
substantial documentation of impact avoidance in flrst study, the applicant may be required to prepare
and/or fund analyses or activities, including, but not limited to:
i. An evaluation by an independent qualifled professional regarding the applicant’s analysis and the
effectiveness of any proposed mitigating measures or programs, to include any recommendations
as appropriate. This shall be paid at the applicant’s expense, and the Administrator shall select the
third-party review professional; and/or
ii. A request for consultation with the Washington Department of Fish and Wildlife, Washington
State Department of Ecology, or the local Native American Tribe or other appropriate agency; and/or
iii. Detailed surface and subsurface hydrologic features both on and abutting the site.
b. Additional Requirements for Geologically Hazardous Areas: Independent secondary review shall
be conducted in accordance with the following:
i. Required – Sensitive and Protected Slopes, and Medium, High, or Very High Landslide
Hazards: All geotechnical reports submitted in accordance with this subsection F, and chapter 4-8
RMC, Permits – General and Appeals, shall be independently reviewed by qualifled specialists
selected by the City, at the applicant’s expense. An applicant may request that independent review
be waived by the Department Administrator in accordance with subsection D of this Section.
ii. Required for Critical Facilities in High Erosion, High Seismic, Medium Coal Mine, or High
Coal Mine Hazards: The City shall require independent review of a geotechnical report addressing
a critical facility, deflned in RMC 4-11-030, by qualifled specialists selected by the City, at the
applicant’s expense. An applicant may request that independent review be waived by the
Department Administrator in accordance with subsection D of this Section.
iii. At City’s Discretion – High Erosion, High Seismic, Medium Coal Mine, or High Coal Mine
Hazards: For any proposal except critical facilities, the City may require independent review of an
applicant’s geotechnical report by qualifled specialists selected by the City, at the applicant’s
expense.
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7. Waiver of Submittal Requirements: An applicant may request that the Administrator waive the report
requirement pursuant to subsection D of this Section, where it has been determined through fleld
documentation that critical areas are not present or as specifled below:
a. Habitat Assessment: In cases where a proposal is not likely to signiflcantly impact the critical habitat
and there is sufficient information to determine the effects of a proposal, an applicant may request that
this report be waived by the Administrator.
b. Streams and Lakes:
i. Stream or Lake Study: This report may only be waived by the Administrator when the applicant
provides satisfactory evidence that:
(a) A road, building or other barrier exists between the water body and the proposed activity, or
(b) The water body or required buffer area does not intrude on the applicant’s lot, and based on
evidence submitted, the proposal will not result in signiflcant adverse impacts to nearby water
bodies regulated under this Section; or
(c) Applicable data and analysis appropriate to the proposed project exists and an additional
study is not necessary.
ii. Stream or Lake Mitigation Plan: This plan may only be waived when no impacts have been
identifled through a stream or lake study.
c. Wetland Assessment: The wetland assessment shall be waived by the Administrator when the
applicant provides satisfactory evidence that a road, building or other barrier exists between the wetland
and the proposed activity, when the buffer area, determined with a wetland categorization, needed or
required will not intrude on the applicant’s lot, or when applicable data and analysis appropriate to the
project proposed exists and an additional report is not necessary.
4-3-050G DEVELOPMENT STANDARDS:
1. General: No proposal shall result in a loss of critical area functions or values. If the application of these
provisions would deny all reasonable use of the property, the applicant may apply for a variance as identifled
in RMC 4-9-250.
2. Critical Area Buffers and Structure Setbacks from Buffers: The following critical area buffers and
structure setbacks from buffers are established for each critical area.
Critical Area Category or Type Critical Area Buffer Width Structure Setback
beyond Buffer1
Flood Hazard Areas
Flood Hazard Areas None None
Channel Migration
Zone None None
Geologically Hazardous Areas
Steep Slopes:2
Sensitive Slopes None3 None3, 4
Protected Slopes5 None3 15 ft.1
Landslide Hazards:2
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Critical Area Category or Type Critical Area Buffer Width Structure Setback
beyond Buffer1
Low None3 None3, 4
Medium None3 None3, 4
High None3 None3, 4
Very High5 50 ft. 15 ft.1
Erosion Hazards:
Low None None
High None None
Seismic Hazards:
Low None None
High None None
Coal Mine Hazards:
Low None3 None3
Medium None3 None3
High None3 None3
Habitat Conservation Areas
Critical Habitats Established by Administrator per RMC 4-3-050G 15 ft.1
Streams and Lakes5
Type F 115 ft. 15 ft.1
Type Np 75 ft. 15 ft.1
Type Ns 50 ft. 15 ft.1
Wellhead Protection Areas
Zones 1 and 2 None None
Wetlands6
Low Impact Land Uses:7
High Habitat
Function
(8-9 points)
Moderate Habitat
Function
(5-7 points)
Low Habitat
Function
(3-4 points)
All Other Scores
15 ft.1
Category I – Bogs &
Natural Heritage
Wetlands
175 ft.
Category I – All
Others 175 ft. 125 ft. 75 ft. 75 ft.
Category II 150 ft. 100 ft. 75 ft. n/a
Category III 100 ft. 75 ft. 50 ft. n/a
Category IV 40 ft. n/a
All Other Land Uses:
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Critical Area Category or Type Critical Area Buffer Width Structure Setback
beyond Buffer1
High Habitat
Function
(8-9 points)
Moderate Habitat
Function
(5-7 points)
Low Habitat
Function
(3-4 points)
All Other Scores
15 ft.1
Category I – Bogs &
Natural Heritage
Wetlands
200 ft.
Category I – All
Others 200 ft. 150 ft. 115 ft. 115 ft.
Category II 175 ft. 150 ft. 100 ft. n/a
Category III 125 ft. 100 ft. 75 ft. n/a
Category IV 50 ft. n/a
Wetlands6
Category Wetland Characteristic Intensity of Impact of Adjacent Land Use
Low Moderate High
I and II Bogs and wetlands of high
conservation value
125 feet 190 feet 250 feet
Habitat score of 8 to 9 150 feet 225 feet 300 feet
Habitat score of 6 to 7 75 feet 110 feet 150 feet
Habitat score of less than 6 and water
quality score of 8 to 9
50 feet 75 feet 100 feet
Not meeting any of the above
characteristics
50 feet 75 feet 100 feet
III Habitat score of 8 to 9 150 feet 225 feet 300 feet
Habitat score of 6 to 7 75 feet 110 feet 150 feet
Habitat score of 3 to 5 40 feet 60 feet 80 feet
IV Any habitat score 25 feet 40 feet 50 feet
Footnotes:
1. The following may be allowed in the building setback area:
a. Landscaping;
b. Uncovered decks, less than eighteen inches (18") above grade;
c. Building overhangs, if such overhangs do not extend more than twenty- four
inches (24") into the setback area; and
d. Impervious ground surfaces, such as driveways and patios, provided that
such improvements may be subject to water quality regulations and
maximum impervious surface limitations.
2. Buffers shall be established from the top, toe, and sides of slopes.
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3. Based upon the results of a geotechnical report and/or independent review,
conditions of approval for developments may include buffers and/or setbacks
from buffers.
4. Unless required pursuant to the adopted building code or Building Official.
5. When a required stream/lake buffer falls within a protected slope or very high
landslide hazard area, the stream/lake buffer width shall extend to the boundary
of the protected slope of very high landslide hazard area.
6. Areas that are functionally and effectively disconnected from the wetland by a
permanent road or other substantially developed surface of sufficient width and
with use characteristics such that buffer functions are not provided shall not be
counted toward the minimum buffer unless these areas can be feasibly removed,
relocated or restored to provide buffer functions.
7. Levels of impacts from proposed land use types: Low intensity land uses include
but are not limited to the following: unpaved trails, low intensity open space
(hiking, bird-watching, preservation of natural resources, etc.) and utility corridor
without a maintenance road and little or no vegetation management.
Level of Impact
From Proposed
Land Use
Types of Land Use
High • Commercial
• Urban
• Industrial
• Institutional
• Mixed-use developments
• Residential (more than 1 unit/acre)
• Roads: federal and state highways, including on-ramps and exits,
state routes, and other roads associated with high-impact land
uses
• Railroads
• Agriculture with high-intensity activities (dairies, nurseries,
greenhouses, growing and harvesting crops requiring annual
tilling, raising and maintaining animals, etc.)
• Open/recreational space with high-intensity uses (golf courses,
ball flelds, etc.)
• Solar farms (utility scale)
Moderate • Residential (1 unit/acre or less)
• Roads: Forest Service roads and roads associated with
moderate-impact land uses
• Open/recreational space with moderate-intensity uses (parks
with paved trails or playgrounds, biking, jogging, etc.)
• Agriculture with moderate-intensity uses (orchards, hay flelds,
light or rotational grazing, etc.)
• Utility corridor or right-of-way used by one or more utilities and
• including access/maintenance road
• Wind farm
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Low • Natural resource lands (forestry/silviculture–cutting of trees
only, not land clearing and removing stumps)
• Open/recreational space with low-intensity uses (unpaved trails,
hiking, birdwatching, etc.)
• Utility corridor without a maintenance road and little or no
vegetation management
• Cell tower
3. Native Growth Protection Areas:
a. Required: A native growth protection area shall be instituted to protect a critical area from any
proposed development for a non-exempt activity as follows:
i. Protected slopes and their associated buffers.
ii. Very high landslide hazard areas and their associated buffers.
iii. Class F, Np, and Ns, as deflned in subsection G7 of this Section, streams or lakes and their
associated buffers.
iv. Category I, II, III, or IV wetlands, as deflned in subsection G9c of this Section, and their
associated buffers.
b. May Be Required: Native growth protection areas may be required for high landslide hazard area
buffers, or for critical habitats and their buffers.
c. Application as Condition of Approval When Otherwise Not Required: A proposal may be
conditioned to provide for native growth protection areas.
d. Standards:
i. Trees, shrubs, and ground cover shall be retained in designated native growth protection areas.
ii. Any activities in native growth protection areas shall be consistent with applicable critical area
regulations.
iii. The City may require enhancement of native growth protection areas to improve functions and
values, reduce erosion or landslide potential, or to meet another identifled purpose of these critical
area regulations.
e. Method of Creation: Native growth protection areas shall be established by one of the following
methods, in order of preference:
i. Tract and Deed Restriction: The applicant shall create a tract via the subdivision and record a
permanent and irrevocable covenant running with the land or deed restriction on the property title
of any critical area management tract or tracts created as a condition of a permit. Such covenant or
deed restriction(s) shall prohibit development, alteration, or disturbance within the tract except for
purposes of habitat enhancement as part of an enhancement project which has received prior
written approval from the City, and from any other agency with jurisdiction over such activity. A
covenant running with the land shall be placed on the tract restricting its separate sale. Each
abutting lot owner or the homeowners’ association shall have an undivided interest in the tract.
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ii. Conservation Easement: The applicant shall, subject to the City’s approval, convey to the City
or other public or nonproflt entity specifled by the City, a recorded easement for the protection of
the critical area and/or its buffer.
iii. Protective Easement: The applicant shall establish and record a permanent and irrevocable
easement on the property title of a parcel or tract of land containing a critical area and/or its buffer
created as a condition of a permit. Such protective easement shall be held by the current and future
property owner, shall run with the land, and shall prohibit development, alteration, or disturbance
within the easement except for purposes of habitat enhancement as part of an enhancement
project which has received prior written approval from the City, and from any other agency with
jurisdiction over such activity.
f. Marking Prior to and During Construction: The location of the outer extent of the critical area buffer
and areas not to be disturbed pursuant to an approved plan shall be marked with high visibility orange
construction fencing and silt fencing in the fleld to prevent disturbance by individuals and equipment
during the development or construction of the approved activity.
g. Permanent Fencing Required: Permanent fencing of the native growth protection area containing
critical area and buffers is required, except when studies document to the satisfaction of the reviewing
official that such fencing will adversely impact habitat connectivity.
h. Signage Required: The common boundary between a native growth protection area and the abutting
land must be permanently identifled. This identiflcation shall include permanent wood or metal signs on
treated or metal posts. Sign locations and size speciflcations shall be approved by the City. Suggested
wording is as follows: “Protection of this natural area is in your care. Alteration or disturbance is
prohibited by law.”
i. Responsibility for Maintenance: Responsibility for maintaining the native growth protection
easements or tracts shall be held by a homeowners’ association, abutting lot owners, the permit
applicant or designee, or other appropriate entity, as approved by the City.
j. Maintenance Covenant and Note Required: The following note shall appear on the face of all plats,
short plats, PUDs, or other approved site plans containing separate native growth protection easements
or tracts, and shall also be recorded as a covenant running with the land on the title of record for all
affected lots on the title: “MAINTENANCE RESPONSIBILITY: All owners of lots created by or beneflting
from this City action, abutting or including a native growth protection easement [tract] are responsible
for maintenance and protection of the easement [tract]. Maintenance includes ensuring that no
alterations occur within the tract and that all vegetation remains undisturbed unless the express written
authorization of the City has been received.”
4. Flood Hazard Areas:
a. Classiflcation: Flood hazard areas are deflned as the land in the fioodplain subject to one percent
(1%) or greater chance of fiooding in any given year. Designation on fiood maps always includes the
letters A or V.
b. Data to Be Used for Existing and Future Flow Conditions: The City shall determine the components
of the fiood hazard areas after obtaining, reviewing and utilizing base fiood elevations and available
fioodplain data for a fiood having a one percent (1%) chance of being equaled or exceeded in any given
year, often referred to as the “one hundred (100) year fiood.” The City may require projections of future
fiow conditions for proposals in unmapped potential fiood hazard areas.
c. General Standards: In all fiood hazard areas, the following standards are required:
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Revised 09/29/25
i. Anchoring – All New Construction: All new construction and substantial improvements shall be
anchored to prevent fiotation, collapse, or lateral movement of the structure resulting from
hydrodynamic and hydrostatic loads including the effects of buoyancy. (Ord. 5977, 8-10-2020)
ii. Anchoring – Manufactured Homes: All manufactured homes must likewise be anchored to
prevent fiotation, collapse or lateral movement, and shall be installed using methods and practices
that minimize fiood damage. Anchoring methods may include, but are not limited to, use of over-
the-top or frame ties to ground anchors (reference FEMA’s Manufactured Home Installation in
Frequently Flooded Areas guidebook for additional techniques).
iii. Construction Materials and Methods:
(a) All new construction and substantial improvements shall be constructed with materials and
utility equipment resistant to fiood damage.
(b) All new construction and substantial improvements shall be constructed using methods,
statutes, codes, rules, regulations and practices that minimize fiood damage .
(c) Electrical, heating, ventilation, plumbing, and air-conditioning equipment and other service
facilities shall be designed and/or otherwise elevated or located so as to prevent water from
entering or accumulating within the components during conditions of fiooding.
iv. Utilities:
(a) All new and replacement water supply systems shall be designed to minimize or eliminate
inflltration of fiood waters into the system. A proposed water well shall be located on high
ground that is not in the fioodway (WAC 173-160-171).
(b) New and replacement sanitary sewage systems shall be designed to minimize or eliminate
inflltration of fiood waters into the systems and discharge from the systems into fiood waters.
(c) On-site waste disposal systems shall be located to avoid impairment to them or
contamination from them during fiooding.
v. Subdivision Proposals:
(a) All subdivision proposals shall be consistent with the need to minimize fiood damage;
(b) All subdivision proposals shall have public utilities and facilities such as sewer, gas,
electrical, and water systems located and constructed to minimize fiood damage;
(c) All subdivision proposals shall have adequate drainage provided to reduce exposure to fiood
damage; and
(d) All subdivision proposals shall show the fiood hazard areas information and boundary on the
subdivision drawing including the nature, location, dimensions, and elevations of the subdivided
area.
vi. Project Review:
(a) A development permit shall be obtained before construction or development begins within
any area of special fiood hazard established in subsection D3c of this Section. The permit shall
be for all structures including manufactured homes, as set forth in chapter 4-11 RMC,
Deflnitions, and for all development including flll and other activities, also as set forth in the
chapter 4-11 RMC, Deflnitions.
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Revised 09/29/25
(b) Where elevation data is not available, either through the fiood insurance study (FIS), Flood
Insurance Rate Map (FIRM), or from another authoritative source (subsection D3f of this
Section), applications for fioodplain development shall be reviewed to assure that proposed
construction will be reasonably safe from fiooding. The test of reasonableness is a local
judgment and includes use of historical data, high water marks, photographs of past fiooding,
etc., where available. Failure to elevate at least two feet (2') above the highest adjacent grade in
these zones may result in higher insurance rates.
(c) Where base fiood elevation data has not been provided or is not available from another
authoritative source, it shall be generated by the applicant.
(d) Review all development permits to determine that:
(1) The permit requirements of this Section have been satisfled;
(2) All other required state and federal permits have been obtained;
(3) The site is reasonably safe from fiooding;
(4) The proposed development is not located in the fioodway. If located in the fioodway,
asensure the encroachment provisions of subsection G4ei of this Section are met.
(5) The proposed development is not located in a channel migration zone. If located in a
channel migration zone, ensure the additional provisions of subsection G4f of this Section
are met; and
(6) Notify FEMA when annexations occur in the Special Flood Hazard Area. (Ord. 5977, 8-
10-2020)
d. Speciflc Standards: In all fiood hazard areas, the following provisions are required:
i. Residential Construction:
(a) In AE and A1-30 zones or other A zoned areas where the base fiood elevation has been
determined or can be reasonably obtained, new construction and substantial improvement of
any residential structure shall have the lowest fioor, which for the purposes of this Section
includes basement or attached garage as described in subsection G4di(e)(4) of this Section,
elevated one foot (1') or more above the base fiood elevation. Mechanical equipment, ductwork,
and utilities shall be elevated at least one foot (1') above the base fiood elevation.
(b) New construction and substantial improvement of any residential structure in an AO zone
shall meet the requirements in Appendix A, attached to Ordinance 5977, or superseding
ordinances.
(c) New construction and substantial improvement of any residential structure in an
Unnumbered A zone, for which a base fiood elevation is not available and cannot be reasonably
obtained, shall be reasonably safe from fiooding, but in all cases the lowest fioor and any
attached garage fioor shall be at least two feet (2') above the highest adjacent grade.
(d) If buildings or manufactured homes are constructed or substantially improved with fully
enclosed areas below the lowest fioor, the areas shall be used solely for parking of vehicles,
building access, or storage.
(e) Fully enclosed areas below the lowest fioor that are subject to fiooding are prohibited, or
shall be designed to automatically equalize hydrostatic fiood forces on exterior walls by allowing
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for the entry and exit of fioodwaters. Designs for meeting this requirement must meet or exceed
the following minimum criteria:
(1) Have a minimum of two (2) openings with a total net area of not less than one (1)
square inch for every square foot of enclosed area subject to fiooding; and
(2) The bottom of all openings shall be no higher than one foot (1') above grade; and
(3) Openings may be equipped with screens, louvers, valves, or other coverings or devices
provided that they permit the automatic entry and exit of fioodwater; and
(4) A garage attached to a residential structure, constructed with the garage fioor slab
below the base fiood elevation, must be designed to allow for the automatic entry and exit
of fioodwaters.
Alternatively, a registered engineer or architect may design and certify engineered openings.
ii. Manufactured Homes:
(a) All manufactured homes to be placed or substantially improved within Zones A1-A30, AH,
and AE on the community’s Flood Insurance Rate Map (FIRM), shall be elevated on a permanent
foundation such that the lowest fioor of the manufactured home is elevated a minimum of one
foot (1') above the base fiood elevation and be secured to an adequately anchored foundation
system to resist fiotation, collapse and lateral movement. Mechanical equipment, ductwork,
and utilities shall be elevated at least one foot (1') above the base fiood elevation.
(b) Manufactured homes to be placed or substantially improved on sites in an existing
manufactured home park or subdivision within Zones A1-30, AH, and AE on the community’s
FIRM that are not subject to the above manufactured home provisions shall be elevated so that
the lowest fioor of the manufactured home is elevated a minimum of one foot (1') above the base
fiood elevation and be secured to an adequately anchored foundation system to resist fiotation,
collapse, and lateral movement. Mechanical equipment, ductwork, and utilities shall be
elevated at least one foot (1') above the base fiood elevation.
(c) If buildings or manufactured homes are constructed or substantially improved with fully
enclosed areas below the lowest fioor, the areas shall be used solely for parking of vehicles,
building access, or storage.
iii. Nonresidential Construction: New construction or substantial improvement of any
commercial, industrial or other nonresidential structure shall meet the requirements of subsection
G4diii(a) or G4diii(b) of this Section:
(a) New construction or substantial improvement of any commercial, industrial or other
nonresidential structure shall meet all of the following requirements:
(1) In AE and A1-30 zones or other A zoned areas where the base fiood elevation has been
determined or can be reasonably obtained, new construction and substantial
improvement of any commercial, industrial, or other nonresidential structure shall have
the lowest fioor, including basement, elevated one foot (1') or more above the base fiood
elevation, or elevated as required by ASCE 24, whichever is greater. Mechanical
equipment and utilities shall be elevated at least one foot (1') above the base fiood
elevation, or as required by ASCE 24, whichever is greater.
(2) If located in an AO zone, the structure shall meet the requirements in Appendix A,
attached to Ordinance 5977, or superseding ordinances.
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(3) If located in an Unnumbered A zone for which a BFE is not available and cannot be
reasonably obtained, the structure shall be reasonably safe from fiooding, but in all cases
the lowest fioor shall be at least two feet (2') above the highest adjacent grade.
(4) If buildings or manufactured homes are constructed or substantially improved with
fully enclosed areas below the lowest fioor, the areas shall be used solely for parking of
vehicles, building access, or storage.
(5) Fully enclosed areas below the lowest fioor that are subject to fiooding are prohibited,
or shall be designed to automatically equalize hydrostatic fiood forces on exterior walls by
allowing for the entry and exit of fioodwaters. Designs for meeting this requirement must
either be certifled by a registered professional engineer or architect or must meet or
exceed the following minimum criteria:
(A) Have a minimum of two (2) openings with a total net area of not less than one (1)
square inch for every square foot of enclosed area subject to fiooding; and
(B) The bottom of all openings shall be no higher than one foot (1') above grade; and
(C) Openings may be equipped with screens, louvers, valves, or other coverings or
devices provided that they permit the automatic entry and exit of fioodwater; and
(D) A garage attached to a residential structure, constructed with the garage fioor slab
below the BFE, must be designed to allow for the automatic entry and exit of
fioodwaters.
Alternatively, a registered engineer or architect may design and certify engineered
openings.
(b) If the requirements of subsection G4diii(a) of this Section are not met, then new construction
and substantial improvement of any commercial, industrial or other nonresidential structure
shall meet all of the following requirements:
(1) Be dry fiood proofed so that below one foot (1') or more above the base fiood level the
structure is watertight with walls substantially impermeable to the passage of water or dry
fiood proofed to the elevation required by ASCE 24, whichever is greater; and
(2) Have structural components capable of resisting hydrostatic and hydrodynamic loads
and effects of buoyancy; and
(3) Be certifled by a registered professional engineer or architect that the design and
methods of construction are in accordance with accepted standards of practice for
meeting provisions of this subsection based on their development and/or review of the
structural design, speciflcations and plans. Such certiflcations shall be provided to the
official as set forth in subsection D3a of this Section; and
(4) Nonresidential structures that are elevated, not fiood proofed, must meet the same
standards for space below the lowest fioor as described in subsection G4diii(a)(5) of this
Section.; and
(c) Applicants who are fiood prooflng nonresidential buildings shall be notifled that fiood
insurance premiums will be based on rates that are one foot (1') below the fiood proofed level
(e.g. a building fiood proofed to the base fiood level will be rated as one foot (1') below).
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Revised 09/29/25
iv. Recreational Vehicles: Recreational vehicles placed on sites within Zones A1-30, AH, and AE on
the community’s FIRM, not including recreational vehicle storage lots, shall either:
(a) Be on the site for fewer than one hundred eighty (180) consecutive days;
(b) Be fully licensed and ready for highway use, on its wheels or jacking system, attached to the
site only by quick disconnect type utilities and security devices, and have no permanently
attached additions; or
(c) Meet the requirements of this subsection G and the elevation and anchoring requirements for
manufactured homes. (Ord. 5977, 8-10-2020; Ord. 6084, 11-14-2022)
e. Additional Restrictions within Floodways: Floodways, deflned in RMC 4-11-060, are located within
fiood hazard areas established in subsection D of this Section. Since the fioodway is an extremely
hazardous area due to the velocity of fiood waters which carry debris, potential projectiles, and erosion
potential, the following provisions apply:
i. Increase in Flood Levels Prohibited: Encroachments, including flll, new construction,
substantial improvements, and other development are prohibited unless certiflcation by a
registered professional engineer demonstrates through hydrologic and hydraulic analyses
performed in accordance with standard engineering practice that:
(a) Encroachments shall not result in any increase in fiood levels during the occurrence of the
base fiood discharge; and
(b) There are no adverse impacts to the subject property or abutting or adjacent properties; and
(c) There are no higher fiood elevations upstream; and
(d) The impact due to fioodway encroachment shall be analyzed using future land use condition
fiows.
ii. Residential Construction in Floodways: Construction or reconstruction of residential
structures is prohibited within designated fioodways, except for:
(a) Repairs, reconstruction, or improvements to a structure which do not increase the ground
fioor area; and
(b) Repairs, reconstruction or improvements to a structure, the cost of which does not exceed
flfty percent (50%) of the market value of the structure either: (1) before the repair,
reconstruction, or improvement is started; or (2) if the structure has been damaged, and is being
restored, before the damage occurred. Work done on structures to comply with existing health,
sanitary, or safety codes or to structures identifled as historic places may be excluded in the flfty
percent (50%).
iii. Compliance Requirements: If this subsection G is satisfled, all new construction and
substantial improvements shall comply with all applicable fiood hazard areas reduction provisions
of this Section.
iv. Bridges Crossing Floodways: In mapped or unmapped fiood hazard areas, future fiow
conditions shall be considered for proposed bridge proposals crossing fioodways.
v. Additional Provisions within AO Zones: Shallow fiooding areas appear on FIRMs as AO zones
with depth designations. The base fiood depths in these zones range from one to three feet (1' to 3')
above ground where a clearly deflned channel does not exist, or where the path of fiooding is
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unpredictable and where velocity fiow may be evident. Such fiooding is usually characterized as
sheet fiow. In addition to other provisions in this code, the following additional provisions also apply
in AO zones:
(a) New construction and substantial improvements of residential structures and manufactured
homes within AO zones shall have the lowest fioor (including basement and mechanical
equipment) elevated above the highest adjacent grade to the structure, one foot (1') or more
above the depth number specifled in feet on the community’s FIRM (at least two feet (2') above
the highest adjacent grade to the structure if no depth number is specifled).
(b) New construction and substantial improvements of nonresidential structures within AO
zones shall either:
(1) Have the lowest fioor elevated above the highest adjacent grade of the building site,
one foot (1') or more above the depth number specifled on the FIRM (at least two feet (2') if
no depth number is specifled); or
(2) Together with attendant utility and sanitary facilities, be above that level described in
G4bv(b)(1) of this Section so that any space below that level is watertight with walls
substantially impermeable to the passage of water and with structural components having
the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. If
this method is used, compliance shall be certifled by a registered professional engineer,
or architect as described in subsection G4diii(b)(3) of this Section.
(c) Require adequate drainage paths around structures on slopes to guide fioodwaters around
and away from proposed structures.
(d) Recreational vehicles placed on sites within AO zones on the community’s FIRM either:
(1) Be on the site for fewer than one hundred eighty (180) consecutive days; or
(2) Be fully licensed and ready for highway use, on its wheels or jacking system, is
attached to the site only by quick disconnect type utilities and security devices, and has
no permanently attached additions; or
(3) Meet the requirements of subsections G4ev(a) and (b) of this Section and the anchoring
requirements for manufactured homes (subsection G4dii of this Section).
vi. AE and A1-30 Zones with Base Flood Elevations but No Floodways: In areas with BFEs (when a
regulatory fioodway has not been designated), no new construction, substantial improvements, or
other development (including flll) shall be permitted within Zones A1-30 and AE on the community’s
FIRM, unless it is demonstrated that the cumulative effect of the proposed development, when
combined with all other existing and anticipated development, will not increase the water surface
elevation of the base fiood more than one foot (1') at any point within the community. (Ord. 5977, 8-
10-2020; Ord. 6084, 11-14-2022)
f. Additional Restrictions within Channel Migration Zone: Channel migration zones, deflned in RMC 4-
11-030 and established in subsection D of this Section, identify hazardous areas with signiflcant erosion
potential; therefore, the following provisions apply to land within channel migration zones:
i. Residential Construction within Channel Migration Zone: New residential development shall
not require new shoreline stabilization. Developable portions of lots shall not be subject to fiooding
or require structural fiood hazard reduction measures within a channel migration zone to support
intended development during the life of the development or use. Prior to approval, analysis of the
site and shoreline characteristics shall demonstrate that new shoreline stabilization is unlikely to
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be necessary for each new lot to support intended development during the life of the development
or use.
ii. All Development: All new construction and substantial improvements shall be constructed
using methods and practices that reduce the risk of damage due to erosion caused by channel
migration.
iii. Bridges: Construction of a new bridge shall be permissible if there is no feasible alternative with
less impact on the critical area, the bridge is located to minimize encroachment into the channel
migration zone, and bridge piers or abutments for bridge crossings are not placed within the severe
channel migration zone.
iv. Mapping Discrepancy: An applicant for a development proposal may submit a report to the
department to determine channel migration zone boundaries or classify channel migration hazard
areas on a speciflc property if there is an apparent discrepancy between the site-speciflc conditions
or data and the adopted channel migration zone mapping. The geomorphic assessment shall be
prepared by a geologist licensed in Washington State with an engineering geology or hydrogeology
specialty license and experience conducting fiuvial geomorphic assessments. If the Administrator
determines there is a discrepancy between the site conditions and the adopted channel migration
zone maps, the City shall make appropriate revisions to the mapped channel migration zone.
fg. Critical Facility: Construction of new critical facilities, as deflned in RMC 4-11-030, shall be, to the
extent possible, located outside the limits of fiood hazard areas (one hundred (100) year) fioodplain and
channel migration zone. Construction of new critical facilities shall be permissible within fiood hazard
areas or and channel migration zones if no feasible alternative site is available. Critical facilities
constructed within fiood hazard areas shall have the lowest fioor elevated three feet (3') or more above
the level of the base fiood elevation (one hundred (100) year) at the site. Floodprooflng and sealing
measures must be taken to ensure that toxic substances will not be displaced by or released into fiood
waters. Access routes elevated to or above the level of the base fiood elevation shall be provided to all
critical facilities to the extent possible.
hg. Compensatory Storage:
i. Compensatory Storage Required: Development proposals and other alterations shall not reduce
the effective base fiood storage volume of the fioodplain. If grading or other activity will reduce the
effective storage volume, compensatory storage shall be created on the site or off the site if legal
arrangements can be made to assure that the effective compensatory storage volume will be
preserved over time. Compensatory storage shall be conflgured so as not to trap or strand
salmonids after fiood waters recede and may be conflgured to provide salmonid habitat or high fiow
refuge whenever suitable site conditions exist and the conflguration does not adversely affect bank
stability or existing habitat. Effective base fiood storage volume shall be based on the elevations
shown in the fiood hazard areas map, identifled in subsection E3 of this Section or as determined
through a study where no base fiood evaluation information exists.
ii. Determining Finished Floor Elevations According to FEMA: The FEMA one hundred (100) year
fiood plain elevations shall be used to establish building flnished fioor elevations to comply with
other National Flood Insurance Program requirements.
5. Geologically Hazardous Areas Deflned:
a. Steep Slope Types:
i. Sensitive Slopes: A hillside, or portion thereof, characterized by: (a) an average slope of twenty
flve percent (25%) to less than forty percent (40%) as identifled in the City of Renton Steep Slope
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Atlas or in a method approved by the City; or (b) an average slope of forty percent (40%) or greater
with a vertical rise of less than flfteen feet (15') as identifled in the City of Renton Steep Slope Atlas
or in a method approved by the City; (c) abutting an average slope of twenty flve percent (25%) to
forty percent (40%) as identifled in the City of Renton Steep Slope Atlas or in a method approved by
the City. This deflnition excludes engineered retaining walls.
ii. Protected Slopes: A hillside, or portion thereof, characterized by an average slope of forty
percent (40%) or greater grade and having a minimum vertical rise of flfteen feet (15') as identifled in
the City of Renton Steep Slope Atlas or in a method approved by the City.
b. Landslide Hazards:
i. Low Landslide Hazard (LL): Areas with slopes less than flfteen percent (15%).
ii. Medium Landslide Hazard (LM): Areas with slopes between flfteen percent (15%) and forty
percent (40%) and underlain by glacially consolidated soils that consist largely of sand, gravel or
glacial till.
iii. High Landslide Hazards (LH): Areas with slopes greater than forty percent (40%), and areas with
slopes between flfteen percent (15%) and forty percent (40%) and underlain by soils consisting
largely of silt and clay of non-glacially consolidated soils, and areas with slopes between flfteen
percent (15%) and forty percent (40%) with adverse groundwater conditions to include slopes that
intersect geologic contacts with a relatively permeable sediment overlying a relatively impermeable
sediment or bedrock and/or where seeps or springs or indicators (e.g., vegetation type) of a shallow
groundwater table are observed on or adjacent to the face of the slope.
iv. Very High Landslide Hazards (LV): Areas of known mapped or identifled landslide deposits.
c. Erosion Hazards:
i. Low Erosion Hazard (EL): Areas with soils characterized by the Natural Resource Conservation
Service (formerly U.S. Soil Conservation Service) as having slight or moderate erosion potential, and
a slope less than flfteen percent (15%).
ii. High Erosion Hazard (EH): Areas with soils characterized by the Natural Resource Conservation
Service (formerly U.S. Soil Conservation Service) as having severe or very severe erosion potential,
and a slope more than flfteen percent (15%).
d. Seismic Soil Liquefaction Hazards:
i. Low Seismic Hazard (SL): Areas underlain by glacially consolidated or otherwise dense soils or
bedrock. These soils generally have site classiflcations of A through D, as deflned in the
International Building Code, 2012.
ii. High Seismic Hazard (SH): Areas underlain by soft or loose, saturated soils, such as alluvium or
artiflcial flll overlaying alluvium. These soils generally have site classiflcations E or F, as deflned in
the International Building Code, 2012.
e. Coal Mine Hazards:
i. Low Coal Mine Hazards (CL): Areas with no known mine workings and no predicted subsidence.
While no mines are known in these areas, undocumented mining is known to have occurred.
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ii. Medium Coal Mine Hazards (CM): Areas where mine workings are deeper than two hundred feet
(200') for steeply dipping seams, or deeper than flfteen (15) times the thickness of the seam or
workings for gently dipping seams. These areas may be affected by subsidence.
iii. High Coal Mine Hazard (CH): Areas with abandoned and improperly sealed mine openings and
areas underlain by mine workings shallower than two hundred feet (200') in depth for steeply
dipping seams, or shallower than flfteen (15) times the thickness of the seam or workings for gently
dipping seams. These areas may be affected by collapse or other subsidence.
f. Protected Slopes, as deflned in subsection G5aii of this Section: Development is prohibited on
protected slopes. Exceptions to this prohibition may be granted pursuant to subsection J of this Section.
g. Sensitive Slopes – Medium, High and Very High Landslide Hazards – High Erosion Hazards: During
construction, weekly on-site inspections under the direction of a licensed geotechnical professional
shall be required at the applicant’s expense. The licensed geotechnical professional directing
inspections shall be the same as the professional that prepared the required geotechnical study for the
geologically hazardous area or shall provide documentation indicating they concur and accept the
conclusions and recommendations in the geotechnical study. Weekly reports prepared by or under the
direction of a Certifled Erosion & Sediment Control Lead (CESCL) documenting erosion control
measures shall be required for High Erosion Hazards.
h. Very High Landslide Hazards:
i. Prohibited Development: Development shall not be permitted on land designated with very high
landslide hazards. Exceptions to this prohibition may be granted pursuant to subsection J of this
Section.
ii. Buffer Modiflcation: The Administrator may increase or decrease the required buffer based upon
the results of a geotechnical report, and any increase or decrease based upon the results of the
geotechnical report shall be documented in writing and included with the project approval. The
modifled standard shall be based on consideration of the best available science as described in
WAC 365-195-905; or where there is an absence of valid scientiflc information, the steps in RMC 4-
9-250 shall be followed.
i. Coal Mine Hazards:
i. Mitigation – Additional Engineering Design and Remediation Speciflcations: After approval of
the mitigation approach proposed as a result of RMC 4-3-050D, and prior to construction, the
applicant shall complete engineering design drawings and speciflcations for remediation. Upon
approval of the plans and speciflcations, the applicant shall complete the remediation. Hazard
mitigation shall be performed by or under the direction of a licensed geotechnical engineer or
engineering geologist. The applicant shall document the hazard mitigation by submitting as-builts
and a remediation construction report.
ii. Hazards Found during Construction: Any hazards found during any development activities shall
be immediately reported to the Development Services Division. Any coal mine hazards shall be
mitigated prior to recommencing construction based upon supplemental recommendations or
reports by the applicant’s geotechnical professional.
iii. Construction in Areas with Combustion: Construction shall not be permitted where surface or
subsurface investigations indicate the possible presence of combustion in the underlying seam or
seams, unless the impact is adequately mitigated in accordance with the recommendations of the
applicant’s geotechnical professional.
6. Habitat Conservation Areas:
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a. Classiflcation of Critical Habitats: Habitats that have a primary association with the documented
presence of non-salmonid or salmonid species proposed or listed by the Federal government or State of
Washington as endangered, threatened, sensitive and/or of local importance. (Ord. 5976, 8-3-2020)
b. Mapping: Critical habitats are identifled by lists, categories and deflnitions of species promulgated by
the Washington State Department of Fish and Wildlife (Non-game Data System Special Animal Species)
as identifled in WAC 220-200-100; in the Priority Habitat and Species Program of the Washington State
Department of Fish and Wildlife; or by rules and regulations adopted currently or hereafter by the U.S.
Fish and Wildlife Service. (Ord. 5976, 8-3-2020)
c. Buffers: The Administrator shall require the establishment of buffer areas for activities in, or adjacent
to, habitat conservation areas when needed to protect flsh and wildlife habitats of importance. Buffers
shall consist of an undisturbed area of native vegetation, or areas identifled for restoration, established
to protect the integrity, functions and values of the affected habitat. Buffer widths shall be based on:
i. Type and intensity of human activity proposed to be conducted on the site and adjacent sites.
ii. Recommendations contained within a habitat assessment report.
iii. Management recommendations issued by the Washington Department of Fish and Wildlife.
d. Alterations Require Mitigation: The Administrator may approve mitigation to compensate for
adverse impacts of a development proposal to habitat conservation areas through use of a federally
and/or state certifled mitigation bank or in-lieu fee program. See subsection L of this Section.
7. Streams and Lakes:
a. Classiflcation System: The following classiflcation system is hereby adopted for the purposes of
regulating Streams and Lakes in the City. This classiflcation system is based on the State’s Permanent
Water Typing System WAC 222-16-030. Stream and lake buffer widths are based on the following rating
system:
i. Type S: Waters inventoried as “Shorelines of the State” under chapter 90.58 RCW. These waters
are regulated under Renton’s Shoreline Master Program Regulations, RMC 4-3-090.
ii. Type F: Waters that are known to be used by flsh or meet the physical criteria to be potentially
used by flsh and that have perennial (year-round) or seasonal fiows.
iii. Type Np: Waters that do not contain flsh or flsh habitat and that have perennial (year-round)
fiows. Perennial stream waters do not go dry any time of a year of normal rainfall. However, for the
purpose of water typing, Type Np waters include the intermittent dry portions of the perennial
channel below the uppermost point of perennial fiow.
iv. Type Ns: Waters that do not contain flsh or flsh habitat and have intermittent fiows. These are
seasonal, non-flsh habitat streams in which surface fiow is not present for at least some portion of
a year of normal rainfall and are not located downstream from any stream reach that is a Type Np
Water. Ns Waters must be physically connected by an above-ground channel system to Type S, F,
or Np Waters.
b. Non-regulated: Waters that are considered “intentionally created” not regulated under this Section
include irrigation ditches, grass-lined swales and canals that do not meet the criteria for Type S, F, Np, or
Ns Non-regulated waters may also include streams created as mitigation. Purposeful creation must be
demonstrated through documentation, photographs, statements and/or other persuasive evidence.
c. Measurement:
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i. Stream/Lake Boundary: The boundary of a stream or lake shall be considered to be its ordinary
high- water mark (OHWM) as deflned in RMC 4-11. The OHWM shall be fiagged in the fleld by a
qualifled consultant when any study is required pursuant to this subsection G7.
ii. Buffer: The boundary of a buffer shall extend beyond the boundaries of the stream or lake to the
width applicable to the stream/lake class as noted in subsection G2 of this Section, Critical Area
Buffers and Structure Setbacks from Buffers. Where streams enter or exit pipes, the buffer in this
subsection shall be measured perpendicular to the OHWM from the end of the pipe along the open
channel section of the stream.
Figure 4-3-050.G.7.c.ii. Buffer measurement at pipe opening.
d. Stream/Lake Buffer Width Requirements:
i. Buffers and Setbacks:
(a) Minimum Stream/Lake Buffer Widths: See subsection G2 of this Section.
(b) Piped or Culverted Streams:
(1) Building structures over a natural stream located in an underground pipe or culvert
except as may be granted by a variance in RMC 4-9-250 are prohibited. Transportation or
utility crossings or other alterations pursuant to subsection J of this Section are allowed.
Pavement over a pre-existing piped stream is allowed. Relocation of the piped stream
system around structures is allowed. If structure locations are proposed to be changed or
the piped stream is being relocated around buildings, a hydrologic and hydraulic analysis
of existing piped stream systems will be required for any development project site that
contains a piped stream to ensure it is sized to convey the one hundred (100) year runoff
level from the total upstream tributary area based on future land use conditions.
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(2) No buffers are required along segments of piped or culverted streams. The City shall
require easements and setbacks from pipes or culverts consistent with stormwater
requirements in RMC 4-6-030 and the adopted drainage manual.
ii. Increased Buffer Width:
(a) Areas of High Blow-down Potential: Where the stream/lake buffer is in an area of high blow-
down potential for trees as identifled by a qualifled professional, the buffer width may be
expanded an additional flfty feet (50') on the windward side.
(b) Habitat Corridors: Where the stream/lake buffer is adjacent to high functioning critical areas
(e.g., wetlands, other streams, other identifled habitats), the stream/lake buffer width shall be
extended to the buffer boundary of the other protected critical area to establish a habitat
corridor as needed to protect or establish contiguous vegetated areas between streams/lakes
and other critical areas.
e. Criteria for Permit Approval – Type F, Np, and Ns: Permit approval for projects on or near regulated
Type F, Np and Ns water bodies shall be granted only if the approval is consistent with the provisions of
this subsection, and complies with one of the following conditions:
i. A proposed action meets the standard provisions of this Section and results in no net loss of
regulated riparian area or shoreline ecological function in the drainage basin where the site is
located; or
ii. A proposed action meets alternative administrative standards pursuant to this Section and the
proposed activity results in no net loss of regulated riparian area or shoreline ecological function in
the drainage basin where the site is located; or
iii. A variance process is successfully completed and the proposed activity results in no net loss of
regulated riparian area or shoreline ecological function in the drainage basin where the site is
located.
f. Incentives for Restoration of Streams Located in an Underground Pipe or Culvert: Daylighting of
culverted watercourses should be encouraged and allowed with the following modifled standards:
i. Residential Zones: Reduced setbacks, lot width and lot depth standards of chapter 4-2 RMC may
be approved without requirement of a variance for lots that abut the daylighted watercourse to
accommodate the same number of lots as if the watercourse were not daylighted.
ii. Mixed Use, Commercial, and Industrial Zones: Where greater lot coverage allowances are
provided for structured parking in chapter 4-2 RMC, lot coverage may be increased to the limit
allowed for structured parking if instead a stream is daylighted. The increase in impervious surface
allowed shall be equal to the area of stream restoration.
(a) Standard buffers may be reduced pursuant to subsection I of this Section. If reduced buffers
in subsection I of this Section along with other development standards of the zone would not
allow the same development level as without the watercourse daylighting, a modiflcation may
be requested as in subsection I2c of this Section.
(b) When designed consistent with the City’s fiood regulations in this subsection G, portions of
the daylighted stream/created buffer may be considered part of compensatory storage in fiood
hazard areas.
(c) Stream relocation is permitted subject to subsection J of this Section.
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8. Wellhead Protection Areas:
a. Applicability: Developments, facilities, uses and activities discussed in this subsection shall comply
with the applicable provisions and restrictions of this Section and chapters 4-4, 4-5, 4-6, 4-9, and 5-5
RMC for the Wellhead Protection Areas, as classifled below, in which the developments, facilities, uses
and activities are located, except as preempted by Federal or State law.
i. Wellhead Protection Areas: Wellhead Protection Areas are the portion of an aquifer within the
zone of capture and recharge area for a well or well fleld owned or operated by the City.
ii. Wellhead Protection Area Zones: Zones of a Wellhead Protection Area are designated to
provide graduated levels of Wellhead Protection Area recharge. Zone boundaries are determined
using best available science documented in the City of Renton Wellhead Protection Plan, an
appendix of the City of Renton Water System Plan, as periodically updated. The following zones may
be designated:
(a) Zone 1: The land area situated between a well or well fleld owned by the City and the three
hundred sixty -flve (365) day groundwater travel time contour.
(b) Zone 1 Modifled: The same land area described for Zone 1 but for the purpose of protecting a
high-priority well, wellfleld, or spring withdrawing from a conflned aquifer with partial leakage in
the overlying or underlying conflning layers. Uses, activities, and facilities located in this area are
regulated as if located within Zone 1 except as provided by this subsection G8.
(c) Zone 2: The land area situated between the three hundred sixty -flve (365) day groundwater
travel time contour and the boundary of the zone of potential capture for a well or well fleld
owned or operated by the City. If the aquifer supplying water to such a well, well fleld, or spring is
naturally protected by conflning overlying and underlying geologic layers, the City may choose
not to subdivide a Wellhead Protection Area into two (2) zones. In such a case, the entire
Wellhead Protection Area will be designated as Zone 2.
iii. Mapping:
(a) Determination of Location within a Zone of a Wellhead Protection Area: In determining
the location of facilities within the zones, the following rules shall apply:
(1) Facilities located wholly within a Wellhead Protection zone shall be governed by the
restrictions applicable to that zone.
(2) Facilities having parts lying within more than one zone of a Wellhead Protection Area
shall be governed as follows: Each part of the facility shall be reviewed and regulated by
the requirements set forth in this Section for the zone in which that part of the facility is
actually located.
(3) Facilities having parts lying both in and out of a Wellhead Protection Area shall be
governed as follows:
(A) That portion which is within a Wellhead Protection Area shall be governed by the
applicable restrictions in this Section; and
(B) That portion which is not in a Wellhead Protection Area shall not be governed by
this Section.
b. Facilities:
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i. Hazardous Materials – Use, Production, Storage, Treatment, Disposal, or Management:
Persons that store, handle, treat, use, or produce a hazardous material as deflned by RMC 4-11-
080, Deflnitions H, which are new, existing, or to be closed, shall be subject to the requirements of
this Section, and as further specifled below:
(a) All applications for development permits for uses in which hazardous materials are stored,
handled, treated, used or produced or which increase the quantity of hazardous materials
stored, handled, treated, used, or produced at a location in the Wellhead Protection Area must
be reviewed for compliance with this chapter by the Department prior to approval.
(b) The focus of review for all permits will be on the hazardous materials that will be stored,
handled, treated, used, or produced; and the potential for these substances to degrade
groundwater quality.
(c) An inventory of hazardous materials on forms provided by the Department shall be submitted
to the Department upon application for a development permit.
(d) Where required by the Department, plans and speciflcations for secondary containment
shall be submitted and shall comply with this subsection G8. Development permits shall not be
issued until plans and speciflcations for secondary containment, if required, have been
approved by the Department.
ii. New Facilities – Zones 1 and 2: All proposals for new facilities within any zone of an Wellhead
Protection Area must be reviewed for compliance with this Section prior to issuance of any
development permits for uses in which hazardous materials are stored, handled, treated, used or
produced or which increase the quantity of hazardous materials stored, handled, treated, used, or
produced.
iii. Prohibited Facilities – Zone 1:
(a) The storage, handling, use, treatment or production of hazardous materials in aggregate
quantities greater than flve hundred (500) gallons shall not be allowed within Zone 1 of a
Wellhead Protection Area. The storage, handling, use, treatment or production of
tetrachloroethylene (e.g., dry-cleaning fiuid) shall not be allowed within Zone 1 of a Wellhead
Protection Area.
(b) No person, persons, corporation or other legal entity shall temporarily or permanently
abandon, close, sell, or otherwise transfer a facility in a Wellhead Protection Area without
complying with the requirements of RMC 4-9-015F, Closure Permit, and permit conditions of this
Section.
iv. Existing Facilities Change in Quantities – Zone 1: In Zone 1 of a Wellhead Protection Area, no
change in operations at a facility shall be allowed that increases the aggregate quantity of
hazardous materials stored, handled, treated, used, or produced with the following exception: An
increase in the quantity of hazardous materials is allowed up to the amount allowed for a new
facility in Zone 1 as provided by subsection C of this Section.
v. Existing Facilities – Allowances in Zone 2: The storage, handling, treatment, use or production
of hazardous materials at existing facilities shall be allowed within Zone 2 of a Wellhead Protection
Area upon compliance with the permit requirements, release reporting requirements, and closure
requirements of this Section.
vi. Requirements for Facilities – Zones 1 and 2: The following conditions in subsections G8bvi(a)
to (d) of this Section will be required as part of any operating permit issued for facilities in Zone 1 of
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a Wellhead Protection Area. Conditions in subsections G8bvi(a) to (c) shall apply to facilities in
Zone 2 of a Wellhead Protection Area.
(a) Secondary Containment – Zones 1 and 2:
(1) Materials Stored in Tanks Subject to DOE – Zones 1 and 2: Hazardous materials
stored in tanks that are subject to regulation by the Washington Department of Ecology
under chapter 173-360 WAC are exempt from containment requirements in subsection
G8bvi(a)(2) of this Section, Secondary Containment – Zones 1 and 2, but are subject to
applicable requirements in RMC 4-5-120, Underground Storage Tank Secondary
Containment Regulations.
(2) Secondary Containment Devices Required in Zones 1 and 2: Every owner of a facility
shall provide secondary containment devices adequate in size to contain on site any
unauthorized release of hazardous materials from any area where these substances are
either stored, handled, treated, used, or produced. Secondary containment devices shall
prevent hazardous materials from contacting soil, surface water, and groundwater and
shall prevent hazardous materials from entering storm drains and, except for authorized
and permitted discharges, the sanitary sewer.
(A) Design requirements for secondary containment devices are as follows:
(i) The secondary containment device shall be large enough to contain the
volume of the primary container in cases where a single container is used to
store, handle, treat, use, or produce a hazardous material. In cases where
multiple containers are used, the secondary containment device shall be large
enough to contain the volume of the largest container. Volumes specifled are in
addition to the design fiow rate of the automatic flre extinguishing system, if
present, to which the secondary containment device is subjected. The secondary
containment device shall be capable of containing the flre fiow for a period of
twenty (20) minutes or more.
(ii) All secondary containment devices shall be constructed of materials of
sufficient thickness, density, and composition to prevent structural weakening of
the containment device as a result of contact with any hazardous material. If
coatings are used to provide chemical resistance for secondary containment
devices, they shall also be resistant to expected abrasion and impact conditions.
Secondary containment devices shall be capable of containing any unauthorized
release for at least the maximum anticipated period sufficient to allow detection
and removal of the release.
(iii) Hazardous materials stored outdoors, and their attendant secondary
containment devices shall be covered to preclude precipitation with the
exception of hazardous materials stored in tanks that have been approved by
and are under permit from the Fire Department. Secondary containment for such
tanks, if uncovered, shall be able to accommodate the volume of precipitation
that could enter the containment device during a twenty -four (24) hour, twenty -
flve (25) year storm, in addition to the volume of the hazardous material stored in
the tank. (Ord. 5806, 6-20-2016)
(iv) Secondary containment devices shall include monitoring procedures or
technology capable of detecting the presence of a hazardous material within
twenty- four (24) hours following a release.
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(v) Hazardous materials shall be removed from the secondary containment
device within twenty -four (24) hours of detection and shall be legally stored or
disposed.
(vi) Areas in which there are fioor drains, catchbasins, or other conveyance piping
that does not discharge into a secondary containment device that meets the
requirements of this chapter shall not be used for secondary containment of
hazardous materials. Closure of existing piping shall be according to procedures
and designs approved by the Department.
(vii) Primary containers shall be impervious to the contents stored therein,
properly labeled, and fltted with a tight cover which is kept closed except when
substances are being withdrawn or used.
(viii) Hazardous materials stored outdoors when the facility is left unsupervised
must be inaccessible to the public. Such techniques as locked storage sheds,
locked fencing, or other techniques may be used if they will effectively preclude
access.
(ix) Stored hazardous materials shall be protected and secured, as needed,
against impact and earthquake to prevent damage to the primary container that
would result in release of hazardous materials that would escape the secondary
containment area.
(b) Monitoring Required: See RMC 4-9-015.
(c) Emergency Collection Devices – Zones 1 and 2: Vacuum suction devices, absorbent
scavenger materials, or other devices approved by the Department shall be present on site (or
available within an hour by contract with a cleanup company approved by the Department), in
sufficient quantity to control and collect the total quantity of hazardous materials plus
absorbent material. The presence of such emergency collection devices and/or cleanup
contract are the responsibility and at the expense of the owner and shall be documented in the
operating permit.
(d) Additional Facility Requirements for Zone 1:
(1) An owner of a facility may, at their own expense, be required to institute a program to
monitor groundwater, surface water runoff, and/or site soils. The Department may require
that the owner of a facility install one or more groundwater monitoring wells in a manner
approved by the Department in order to accommodate the required groundwater
monitoring. Criteria used to determine the need for site monitoring shall include, but not
be limited to, the proximity of the facility to the City’s production or monitoring wells, the
type and quantity of hazardous materials on site, and whether or not the hazardous
materials are stored in underground vessels.
(2) An owner may be required to pave all currently unpaved areas of their facility that are
subject to any vehicular use or storage, use, handling, or production of hazardous
materials.
(3) An owner may be required to meet the provisions of RMC 4-6-030E4 if the nature of the
business involves the use of hazardous materials outside of fully enclosed structures, and
the City evaluates the existing stormwater collection and conveyance system.
(4) The owner may be required to test interior wastewater plumbing and the building side
sewer for tightness according to subsection G8gi(c) of this Section, Pipeline Requirements
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– Zone 1, and the City reserves the right to require that such wastewater conveyance be
repaired or replaced according to subsection G8gi of this Section, Pipeline Requirements –
Zone 1.
(5) An owner shall be paid by the City flfty percent (50%) of documented capital costs up to
twenty- flve thousand dollars ($25,000.00) for required installation and construction of
monitoring wells, site paving, wastewater conveyance, and stormwater improvements as
required in subsections G8bvi(d)(1) through (4) of this Section, Groundwater Monitoring
and Paving. Payment by the City shall be made according to adopted administrative rules.
c. Limited Exemptions: Activities that are exempt from some, but not all, provisions of this Section are
listed below. Whether the exempted activities are also exempt from permits will be determined based
upon application of chapters 4-8 and 4-9 RMC, or other applicable sections of the Renton Municipal
Code.
i. Hazardous Materials:
(a) Materials for Sale in Original Small Containers: Hazardous materials offered for sale in
their original containers of flve (5) gallons or less shall be exempt from requirements in
subsection G8bvi of this Section.
(b) Activities Exempt from Specifled Wellhead Protection Areas Requirements: The following
are exempt from requirements in subsections G8bvi(a) through (d) of this Section, the
requirements pertaining to review of proposed facilities in subsection C5d of this Section,
Prohibited Changes in Land Use and Types of New Facilities – Wellhead Protection Areas, and
the requirements pertaining to prohibited facilities in subsection G8biii(a) of this Section:
(1) Hazardous materials use, storage, and handling in de minimis amounts (aggregate
quantities totaling twenty (20) gallons or less at the facility or construction site). Weights
of solid hazardous materials will be converted to volumes for purposes of determining
whether de minimis amounts are exceeded. Ten (10) pounds shall be considered equal to
one gallon.
(2) Noncommercial residential use, storage, and handling of hazardous materials;
provided, that no home occupation business (as deflned by chapter 4-11 RMC) that uses,
stores, or handles more than twenty (20) gallons of hazardous material is operated on the
premises.
(3) Hazardous materials in fuel tanks and fiuid reservoirs attached to a private or
commercial motor vehicle and used directly in the operation of that vehicle.
(4) Fuel oil used in existing heating systems.
(5) Hazardous materials used, stored, and handled by the City of Renton in water
treatment processes and water system operations.
(6) Fueling of equipment not licensed for street use; provided, that such fueling activities
are conducted in a containment area that is designed and maintained to prevent
hazardous materials from coming into contact with soil, surface water, or groundwater
except for refueling associated with construction activity regulated by RMC 4-4-030(C)(8),
Construction Activity Standards – Zones 1 and 2.
(7) Hazardous materials contained in properly operating sealed units (transformers,
refrigeration units, etc.) that are not opened as part of routine use.
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(8) Hazardous materials in fuel tanks and fiuid reservoirs attached to private or
commercial equipment and used directly in the operation of that equipment.
(9) Hazardous materials in aerosol cans.
(10) Hazardous materials at multifamily dwellings, hotels, motels, retirement homes,
convalescent centers/nursing homes, mobile or manufactured home parks, group homes,
and daycare family homes or centers when used by owners and/or operators of such
facilities for on-site operation and maintenance purposes.
(11) Hazardous materials used for janitorial purposes at the facility where the products are
stored.
(12) Hazardous materials used for personal care by workers or occupants of the facility at
which the products are stored including but not limited to soaps, hair treatments,
grooming aids, health aids, and medicines.
(c) Uses, Facilities, and Activities in Zone 1 Modifled Wellhead Protection Areas Exempt
from Specifled Wellhead Protection Areas Requirements: Facilities located in the Zone 1
Modifled Wellhead Protection Areas are exempt from the following:
(1) Prohibited facilities requirements in subsection G8biii(a) of this Section except that the
storage, handling, use, treatment, and production of tetrachloroethylene (e.g., dry-
cleaning fiuid) shall be prohibited;
(2) Additional facility requirements in subsection G8bvi(d) of this Section;
(3) Wastewater requirements in RMC 4-6-040J1a but shall be subject to Zone 2
requirements in RMC 4-6-040J2;
(4) The prohibition of septic systems; and
(5) Surface water management requirements of RMC 4-6-030E except that Zone 2
requirements contained in RMC 4-6-030E shall apply.
d. Use of Pesticides and Nitrates – All Wellhead Protection Areas:
i. Use of Pesticides: The application of hazardous materials such as pesticides shall be allowed in
a Wellhead Protection Area, except within one hundred feet (100') of a City owned well or two
hundred feet (200') of a City owned spring; provided, that:
(a) The application is in strict conformity with the use requirements as set forth by the EPA and
as indicated on the containers in which the substances are sold.
(b) Persons who are required to keep pesticide application records by RCW 17.21.100.1 and
WAC 16-228-190 shall provide a copy of the required records to the Department within seventy -
two (72) hours of the application.
ii. Fertilizers/Nitrate-Containing Materials: The application of fertilizers containing nitrates shall
be allowed in a Wellhead Protection Area except within one hundred feet (100') of a City owned well
or two hundred feet (200') of a spring; provided, that:
(a) No application of nitrate-containing materials shall exceed one-half (0.5) pound of nitrogen
per one thousand (1,000) square feet per single application and a total yearly application of flve
(5) pounds of nitrogen per one thousand (1,000) square feet; except that an approved slow-
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release nitrogen may be applied in quantities of up to nine-tenths (0.9) pound of nitrogen per one
thousand (1,000) square feet per single application and eight (8) pounds of nitrogen per one
thousand (1,000) square feet per year; and
(b) Persons who apply fertilizer containing nitrates to more than one contiguous acre of land
located in the Wellhead Protection Area either in one or multiple application(s) per year shall
provide to the Department within seventy- two (72) hours of any application the following
information:
(1) The name, address, and telephone number of the person applying the fertilizer;
(2) The location and land area of the application;
(3) The date and time of the application;
(4) The product name and formulation;
(5) The application rate.
e. Wastewater Disposal Requirements – Zones 1 and 2: Refer to RMC 4-6-040J, Sanitary Sewer
Standards, Additional Requirements that Apply within Zones 1 and 2 of an Aquifer Protection Area.
f. Surface Water Requirements – Zones 1 and 2: Refer to RMC 4-6-030E, drainage plan requirements
and methods of analysis for additional surface water requirements applicable within Zones 1 and 2 of a
Wellhead Protection Area.
g. Pipeline Requirements:
i. Pipeline Requirements – Zone 1:
(a) Materials: All new and existing pipelines, as deflned by RMC 4-11-160, in Zone 1 shall be
constructed or repaired in accordance with material speciflcations contained in this Section.
(b) Maintenance Required for Existing Pipelines: All existing product pipelines in Zone 1 shall
be repaired and maintained in accordance with best management practices and best available
technology.
(c) Testing Required for New Pipelines: All new pipelines constructed in Zone 1 shall be tested
for leakage in conformance with the following provisions prior to being placed into service.
(1) Pipeline leakage testing shall be conducted in accordance with best available
technology, to the satisfaction of the Department.
(2) Pipeline leakage testing methods shall be submitted to the Department for review prior
to testing and shall include a detailed description of the testing methods and technical
assumptions; accuracy and precision of the test; proposed testing durations, pressures,
and lengths of pipeline to be tested; and scale drawings of the pipeline(s) to be tested.
(3) Upon completion of testing, pipeline leakage testing results shall be submitted to the
Department and shall include: record of testing durations, pressures, and lengths of
pipeline tested; and weather conditions at the time of testing.
(4) Routine leakage testing of new pipelines constructed in Zone 1 may be required by the
Department.
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h. Construction Activity Standards – Zones 1 and 2: Persons engaged in construction activities as
deflned in RMC 4-11-030, Deflnitions C, shall comply with subsection G8 of this Section.
i. Fill Material Requirements – Zones 1 and 2: Refer to RMC 4-4-060N4, Fill Material – Zones 1 and 2,
regarding quality of flll and flll material source statement requirements within Critical Aquifer Recharge
Areas.
j. Regulations for Existing Solid Waste Landfllls – Zones 1 and 2:
i. Materials: Earth materials used as flll or cover at a solid waste landflll shall meet the
requirements of RMC 4-4-060N4, Fill Material.
ii. Groundwater Monitoring: The Department shall have the authority to require an owner of a solid
waste landflll to implement a groundwater monitoring program equal to that described by King
County Board of Health Title 10 (King County Solid Waste Regulations) Section 10.72.020 and a
corrective action program equal to that described by Section 10.72.030. The Department shall have
the authority ascribed to the health officer in said regulations. Quarterly reports shall be provided to
the Department detailing groundwater monitoring activity during the preceding three (3) months.
Reports detailing corrective action required by the Department shall be submitted according to a
written schedule approved by the Department.
k. Fuel Oil Heating Systems – Zones 1 and 2: Owners of facilities and structures shall comply with
subsections C5cii(i) and C5ciii(f) of this Section, Prohibited Activities – Wellhead Protection Areas,
Zones 1 and 2, relating to conversion of heating systems to fuel oil and installation of new fuel oil heating
systems.
9. Wetlands:
a. Applicability: Wetland regulations apply to sites containing or abutting wetlands, deflned in RMC 4-
11-230, as described below. The City categorizes wetlands according to the most current version of the
Washington State Wetland Rating System for Western Washington.
b. Delineation of Regulatory Edge of Wetlands:
i. Methodology: For the purpose of regulation, the exact location of the wetland edge shall be
determined by the wetlands specialist hired at the expense of the applicant through the
performance of a fleld investigation in accordance with the approved federal wetland delineation
manual and applicable regional supplements.
ii. Adjustments to Delineation by City: Where the applicant has provided a delineation of the
wetland edge, the City shall review and may render adjustments to the edge delineation. In the
event the adjusted edge delineation is contested by the applicant, the City shall, at the applicant’s
expense, obtain the services of an additional qualifled wetlands specialist to review the original
study and render a flnal delineation.
c. Wetland Categorization or Categorization System: The following categorization system is hereby
adopted for the purposes of regulating wetlands in the City. The City may accept a dual wetland
categorization for a wetland exhibiting a combination of Category I and II features or a combination of
Category I and III features. The City will not accept a dual rating for a Category II wetland, such as a
combined Category II and III rating. Dual ratings for a Category I wetland shall be consistent with the
Washington State Wetland Rating System for Western Washington – 2014 Update (October 2014), or as
amended hereafter. Wetlands buffer widths, replacement ratios and avoidance criteria shall be based
on Wetland Mitigation in Washington State, Part 1: Agency Policies and Guidance, Version 2 (Ecology
Publication No. 21-06-003, April 2021) and the following ratings:
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i. Category I Wetlands: Category I wetlands are those wetlands of exceptional value in terms of
protecting water quality, storing fiood and stormwater, and/or providing habitat for wildlife as
indicated by a rating system score of twenty -three (23) points or more on the state rating system
referenced above. These are wetland communities of infrequent occurrence that often provide
documented habitat for critical, threatened or endangered species, and/or have other attributes
that are very difficult or impossible to replace if altered.
ii. Category II Wetlands: Category II wetlands have signiflcant value based on their function as
indicated by a rating system score of between twenty (20) and twenty -two (22) points. They do not
meet the criteria for Category I rating but occur infrequently and have qualities that are difficult to
replace if altered.
iii. Category III Wetlands: Category III wetlands have important resource value as indicated by a
rating system score of between sixteen (16) and nineteen (19) points.
iv. Category IV Wetlands: Category IV wetlands are wetlands of limited resource value as indicated
by a rating system score between nine (9) and flfteen (15) points. They typically have vegetation of
similar age and class, lack special habitat features, and/or are isolated or disconnected from other
aquatic systems or high -quality upland habitats.
d. Wetland Buffers:
i. Standard Buffer Widths: See subsection G2 of this Section, Critical Area Buffers and Structure
Setbacks from Buffers.
ii. Independent Buffer Study: The Administrator shall have the authority to approve proposed
alternate buffer widths based on a qualifled professional’s wetland study, provided the criteria
below are met. Determinations made by the Administrator pursuant to this subsection may be
appealed to the Hearing Examiner.
(a) The applicant funds the wetland study; and
(b) The wetland study shows why the standard buffer widths are unnecessary and how the
proposed alternate buffer will provide an equivalent ecological protection as provided by the
City standards; and
(c) The wetland study demonstrates how it meets best available science as identifled in
Wetlands in Washington State, Volume 1: A Synthesis of the Science (Ecology Publication No.
05-06-006, March 2005), and Wetlands in Washington State, Volume 2: Managing and Protecting
Wetlands (Ecology Publication No. 04-06-008, April 2005), Wetland Mitigation in Washington
State Part 1: Agency Policies and Guidance, Version 2 (Ecology Publication No. 21-06-003, April
2021), and Calculating Credits and Debits for Compensatory Mitigation in Wetlands of Western
Washington (Ecology Publication No. #10-06-011, March 2012).
iii. Measurement of Buffers: All buffers shall be measured from the wetland boundary as surveyed
in the fleld pursuant to the requirements of this subsection.
iv. Increased Wetland Buffer Width: Each applicant shall document in the required wetland
assessments whether the criteria in this subsection G9d are or are not met and increased wetland
buffers are warranted. Based on the applicant’s report or third- party review, increased standard
buffer widths may be required in unique cases. Such determination shall be attached as a condition
of project approval. Unique cases shall include but not be limited to:
(a) The wetland is used by species listed by the Federal or the State government as threatened,
endangered and sensitive species and State-listed priority species, essential habitat for those
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species or has unusual nesting or resting sites such as heron rookeries or raptor nesting trees or
evidence thereof; or
(b) The buffer or adjacent uplands have a slope greater than flfteen percent (15%) or is
susceptible to erosion and standard erosion control measures will not effectively prevent
adverse wetland impacts.
(c) The area is very fragile, or when a larger buffer is necessary to protect wetlands functions and
values.
e. Cooperative Wetland Compensation: Mitigation Banks, In-Lieu Fee Programs, or Special Area
Management Programs (SAMP):
i. Applicability: The City encourages and will facilitate and approve cooperative projects wherein a
single applicant or other organization with demonstrated capability may undertake a compensation
project under the following circumstances:
(a) Restoration or creation on site may not be feasible due to problems with hydrology, soils, or
other factors; or
(b) Where the cooperative plan is shown to better meet established regional goals for fiood
storage, fiood conveyance, habitat or other wetland functions.
ii. Process: Applicants proposing a cooperative compensation project shall:
(a) Submit a permit application;
(b) Demonstrate compliance with all standards;
(c) Demonstrate that long-term management will be provided; and
(d) Demonstrate agreement for the project from all affected property owners of record.
iii. Mitigation Banks: Mitigation banks are deflned as sites which may be used for restoration,
creation and/or mitigation of wetland alternatives from a different piece of property than the
property to be altered within the same drainage basin. The City of Renton maintains a mitigation
bank. A list of City mitigation bank sites is maintained by the Public Works Department. With the
approval of Administrator and the Public Works Department, non-City-controlled mitigation banks
may be established and utilized. If credits are from a mitigation bank are to be used for Federal or
State permits, the bank must be certifled under State rules. If approved, compensation payments
received as part of a mitigation or creation bank must be received prior to the issuance of an
occupancy permit.
iv. In-Lieu Fee Programs: In-lieu fee mitigation involves the restoration, creation, enhancement, or
preservation of aquatic resources through funds paid to a governmental or non-proflt natural
resources management entity to satisfy compensatory mitigation for Federal, State, and local
permits. Both the U.S. Army Corps of Engineers (33 CFR Parts 325 and 332) and Washington State
(WAC 173-700) support the use of in-lieu fee programs. The City of Renton is located within the
service area of the King County Mitigation Reserves In-Lieu Fee Program, which may be used by
applicants with the approval of the Administrator and Public Works Department provided the
mitigation occurs within the City of Renton and the same drainage basin.
v. Special Area Management Programs: Special area management programs are those wetland
programs agreed upon through an interjurisdictional planning process involving the U.S. Army
Corps of Engineers, the Washington State Department of Ecology, any affected counties and/or
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cities, private property owners and other parties of interest. The outcome of the process is a
regional wetlands permit representing a plan of action for all wetlands within the special area.
4-3-050H ALTERATIONS TO CRITICAL AREAS AND/OR BUFFERS – GENERAL REQUIREMENTS:
1. General Purpose: The typically required critical area buffers may be reduced to no less than the
minimums set forth in this subsection where the City is able to verify that the proposal will result in no net
loss of functions or values as documented in a study prepared by a qualifled professional. Greater buffer
width reductions require review as a variance pursuant to subsection K of this Section.
2. Authority and Documentation of Required Findings: Based upon an applicant’s request, and the
acceptance of a wetland and/or stream or lake study, mitigation and enhancement plan, the Administrator
may approve an alteration to the minimum buffer widths where the applicant can demonstrate that through
enhancing the buffer and the use of low impact development strategies the reduced buffer will function at a
higher level than the standard buffer. Determinations and evidence shall be included in the application flle.
The City shall also evaluate all proposals using the following criteria, in the order below. The development
plan will:
a. Avoid any disturbances to the critical area or buffer;
b. Minimize any critical area or buffer impacts;
c. Compensate for any critical area or buffer impacts;
d. Restore any critical area or buffer temporarily impacted or lost;
e. Create new critical areas and buffers for those lost; and
f. Enhance an existing degraded buffer to compensate for lost functions and values in addition to
restoring or creating a critical area.
3. Studies Required: The City’s determination shall be based on speciflc site studies by recognized experts.
Impacts and mitigation shall be based on consideration of Wetland Mitigation in Washington State Part 1:
Agency Policies and Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021) and Calculating
Credits and Debits for Compensatory Mitigation in Wetlands of Western Washington (Ecology Publication
No. #10-06-011, March 2012).
4. Surety, Mitigation, and Monitoring Required: The City will require long-term monitoring of the project
pursuant to subsection L3 of this Section.
5. Corrective Actions Required: Corrective actions will be required if adverse impacts to critical areas or
buffers are discovered during the monitoring period.
6. Public Notice Required: Public notiflcation shall be given as follows:
a. For applications that are not otherwise subject to notices of application pursuant to chapter 4-8 RMC,
notice of the critical area and/or buffer alteration shall be given by posting the site and notifying abutting
or adjacent property owners with the potential to be impacted, in accordance with chapter 4-8 RMC.
Upon determination by the Administrator to allow or disallow an alteration, notiflcation of parties of
record, if any, shall be made.
b. For applications that are subject to notices of application, the critical area and/or buffer alteration or
request for determination to allow an alteration shall be included with notice of application. If the
determination to allow or disallow an alteration of the mitigation requirements is not known at the time
of the notice of application, written notice to abutting or adjacent property owners shall be given instead
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at the time of the SEPA determination. Upon determination to allow or disallow an alteration,
notiflcation of parties of record, if any, shall be made.
4-3-050I ALTERATIONS TO CRITICAL AREAS BUFFERS:
1. Maximum Permissible Administrative Alterations to Critical Areas Buffers – Alteration of Critical Area
Buffers: The required critical area buffers may be reduced to no less than the minimums set forth in this
subsection. Greater buffer width reductions require review as a variance pursuant to RMC 4-9-250.
Critical Area Category or Type Reduced Buffer: Minimum Widths
Possible
Averaged Buffer: Minimum Widths
Possible
Geologically Hazardous Areas
Landslide Hazard Areas:
Very High Based on City acceptance of a geotechnical
report1 N/A
Streams and Lakes
Type F 90 feet2 75 feet3
Type Np 60 feet2 37.5 feet3
Type Ns 40 feet2 25 feet3
Wetlands
Wetland buffer widths shall be reduced by no more than 25% of the buffer required in subsection G of this Section.
1. Subject to approval pursuant to the criteria in RMC 4-3-050G5hii.
2. Subject to approval pursuant to the criteria in RMC 4-3-050I2a.
3. Subject to approval pursuant to the criteria in RMC 4-3-050I2b.
2. Streams:
a. Criteria for Reduction of Degraded Stream Buffer Width with Enhancement: A reduced buffer will
be approved in a degraded stream buffer only if:
i. It will provide an overall improvement in water quality; and
ii. It will provide an overall enhancement to flsh, wildlife, or their habitat; and
iii. It will provide a net improvement in drainage and/or stormwater detention capabilities; and
iv. It will not be materially detrimental to any other property or the City as a whole; and
v. It will provide all exposed areas with stabilized native vegetation, as appropriate; and
vi. The request is not made in conjunction with buffer reduction, and
vii. It will provide, as part of the buffer reduction request, buffer enhancement plan prepared by a
qualifled professional and fund a review of the plan by the City’s consultant. The plan shall assess
habitat, water quality, stormwater detention, groundwater recharge, shoreline protection, and
erosion protection functions of the buffer; assess the effects of the proposed modiflcation on those
functions; and address the six (6) criteria listed above.
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b. Criteria for Approval of Averaged Stream Buffer: Buffer width averaging may be allowed only where
the applicant demonstrates all of the following:
i. There are existing physical improvements in or near the water body and associated riparian area;
and
ii. Buffer width averaging will result in no net loss of stream/lake/riparian ecological function; and
iii. The total area contained within the buffer after averaging is no less than that contained within the
required standard buffer width prior to averaging; and
iv. The proposed buffer standard is based on consideration of the best available science as
described in WAC 365-195-905; and
v. Where the buffer width is reduced by averaging pursuant to this subsection, buffer enhancement
shall be required.
c. Criteria for Approval of Reduced Buffer for Type Np and Ns Streams to be Daylighted: An
applicant may request that the Administrator grant a modiflcation as follows:
i. Modiflcations may be requested for a reduction in stream buffers for Type Np and Ns
watercourses proposed to be daylighted, below the stream buffer reduction levels of subsection I1
of this Section.
ii. In addition to the criteria of RMC 4-9-250D, Modiflcation Procedures, the following criteria shall
apply:
(a) The buffer is lowered only to the amount necessary to achieve the same amount of
development as without the daylighting; and
(b) The buffer width is no less than flfty feet (50') on a Type Np watercourse and twenty- flve feet
(25') on a Type Ns watercourse; and
(c) The proposed modiflcation is based on consideration of the best available science as
described in WAC 365-195-905.
3. Wetlands:
a. Criteria for Reduction of Wetland Buffer Width with Enhancement: The reviewing official must flnd
that the proposal meets all the following criteria:
i. The reduced buffer will function at a higher level than the standard buffer; and
ii. An enhanced buffer shall never be less than seventy flve percent (75%) of the standard width at
its narrowest point; and
iii. The buffer area has less than flfteen percent (15%) slopes and no direct or indirect, short-term or
long-term, adverse impacts to regulated wetlands, as determined by the City, and
iv. The proposal shall rely upon a site-speciflc evaluation and documentation of buffer adequacy
based upon Wetlands in Washington State, Volume 1: A Synthesis of the Science (Ecology
Publication No. 05-06-006, March 2005), and Wetlands in Washington State, Volume 2: Managing
and Protecting Wetlands (Ecology Publication No. 04-06-008, April 2005), and Wetland Mitigation in
Washington State Part 1: Agency Guidance, Version 2 (Ecology Publication No. 21-06-003, April
2021) or similar approaches; and
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v. The proposed buffer standard is based on consideration of the best available science as
described in WAC 365-195-905; and
b. Criteria for Averaging of Wetland Buffer Width: Averaging may be allowed only where the applicant
demonstrates all of the following:
i. There are existing physical improvements in or near the wetland and buffer; and
ii. That width averaging will not adversely impact the wetland function and values; and
iii. That the total area contained within the wetland buffer after averaging is no less than that
contained within the required standard buffer prior to averaging; and
iv. A site-speciflc evaluation and documentation of buffer adequacy based upon Wetlands in
Washington State, Volume 1: A Synthesis of the Science (Ecology Publication No. 05-06-006, March
2005), and Wetlands in Washington State, Volume 2: Managing and Protecting Wetlands (Ecology
Publication No. 04-06-008, April 2005), and Wetland Mitigation in Washington State Part 1: Agency
Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021) or similar approaches have
been conducted. The proposed buffer standard is based on consideration of the best available
science as described in WAC 365-195-905; and
v. In no instance shall the buffer width be reduced by more than seventy flve percent (75%) of the
standard buffer. Greater buffer width reductions require review as a variance pursuant to RMC 4-9-
250B; and
vi. Buffer enhancement in the areas where the buffer is reduced shall be required on a case-by-case
basis where appropriate to site conditions, wetland sensitivity, and proposed land development
characteristics.
4-3-050J ALTERATIONS TO CRITICAL AREAS:
1. Criteria for Modifying Geologically Hazardous Area Standards:
a. An applicant may request that the Administrator grant a modiflcation to allow:
i. Regrading of any slope which was created through previous mineral and natural resource recovery
activities or was created prior to adoption of applicable mineral and natural resource recovery
regulations or through public or private road installation or widening and related transportation
improvements, railroad track installation or improvement, or public or private utility installation
activities; and/or
ii. Filling against the toe of a natural rock wall or rock wall created through mineral and natural
resource recovery activities or through public or private road installation or widening and related
transportation improvements, railroad track installation or improvement or public or private utility
installation activities;
b. Process: The following procedures shall apply to any of the above activities:
i. The applicant shall submit a geotechnical report describing any potential impacts of the proposed
modiflcation and any necessary mitigation measures;
ii. All submitted reports shall be independently reviewed by qualifled specialists selected by the
City at the applicant’s expense;
iii. The Administrator may grant, condition, or deny the request based upon the proposal’s
compliance with the applicable modiflcation criteria of RMC 4-9-250D; and
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iv. Any slope which remains forty percent (40%) or steeper following site development shall be
subject to all applicable geologic hazard regulations for steep slopes and landslide hazards, in this
Section; and
v. In addition to the criteria of RMC 4-9-250D, Modiflcation Procedures, the following criteria shall
apply: The proposed modiflcation is based on consideration of the best available science as
described in WAC 365-195-905.
2. Alterations Within Streams and Lakes or Associated Buffers.
a. Criteria for Administrative Approval of Transportation Crossings in Stream/Lake or Buffer Areas:
Construction of vehicular or non-vehicular transportation crossings may be permitted in accordance
with an approved stream/lake study subject to the following criteria:
i. The proposed route is determined to have the least impact on the environment, while meeting City
Comprehensive Plan Transportation Element requirements and standards in RMC 4-6-060; and
ii. The crossing minimizes interruption of downstream movement of wood and gravel; and
iii. Transportation facilities in buffer areas shall not run parallel to the water body; and
iv. Crossings occur as near to perpendicular with the water body as possible; and
v. Crossings are designed according to the Washington Department of Fish and Wildlife Fish Water
Crossing Design Guidelines (2013) and the National Marine Fisheries Service (NMFS) 2022
Guidelines for Salmonid Passage at Stream Crossings in Oregon, Washington, and Idaho. These
guidelines National Marine Fisheries Service Guidelines for Salmonid Passage at Stream Crossings,
2000, as may be updated, or replaced by equivalent manuals as determined by the Administrator;
and
vi. Seasonal work windows are determined and made a condition of approval; and
vii. Mitigation criteria of subsection L of this Section are met.
b. Criteria for Administrative Approval of Utilities in Stream/Lake or Buffer: New utility lines and
facilities may be permitted to cross water bodies in accordance with an approved stream/lake study, if
they comply with the following criteria:
i. Fish and wildlife habitat areas shall be avoided to the maximum extent possible; and
ii. The utility is designed consistent with one or more of the following methods:
(a) Installation shall be accomplished by boring beneath the scour depth and hyporheic zone of
the water body and channel migration zone; or
(b) The utilities shall cross at an angle greater than sixty (60) degrees to the centerline of the
channel in streams or perpendicular to the channel centerline; or
(c) Crossings shall be contained within the footprint of an existing road or utility crossing; and
iii. New utility routes shall avoid paralleling the stream or following a down-valley course near the
channel; and
iv. The utility installation shall not increase or decrease the natural rate of shore migration or
channel migration; and
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v. Seasonal work windows are determined and made a condition of approval; and
vi. Mitigation criteria of subsection L of this Section are met.
c. Administrative Approval of In-Water Structures or In-Water Work: In accordance with an approved
stream or lake study, in-water structures or work may be permitted, subject to the following: In-stream
structures, such as, but not limited to, in-stream ponds, retention and detention facilities, tide gates,
dams, and weirs, shall be allowed as part of an approved watershed basin restoration project approved
by the City of Renton, and in accordance with mitigation criteria of subsection L of this Section. The
applicant will obtain and comply with State or Federal permits and requirements.
d. Administrative Approval of Dredging: Dredging may be permitted only when:
i. Dredging is necessary for fiood hazard areas reduction purposes, if a deflnite fiood hazard area
would exist unless dredging were permitted; or
ii. Dredging is necessary to correct problems of material distribution and water quality, when such
problems are adversely affecting aquatic life; or
iii. Dredging is associated with a stream habitat enhancement or creation project not otherwise
exempt in subsection C of this Section; or
iv. Dredging is necessary to protect public facilities; or
v. Dredging is required as a maintenance and operation condition of a federally funded fiood hazard
areas reduction project or a hazard mitigation project; and
vi. Dredging is done so as to meet applicable mitigation criteria of subsection L of this Section.
e. Administrative Approval of Stream Relocation: Stream relocation may be allowed when analyzed in
an accepted stream or lake assessment, and when the following criteria and conditions are met:
i. Stream relocation may only be permitted if associated with:
(a) A public fiood hazard areas reduction/habitat enhancement project approved by appropriate
state and/or federal agencies; or
(b) Expansion of public road or other public facility improvements where no feasible alternative
exists; or
(c) A public or private proposal restoring a water body and resulting in a net beneflt to on- or off-
site habitat and species.
ii. The following conditions also apply to any stream relocation proposal meeting one or more of the
above criteria:
(a) Buffer widths shall be based upon the new stream location; provided, that the buffer widths
may be reduced or averaged if meeting criteria of subsection I or J of this Section. Where
minimum required buffer widths are not feasible for stream relocation proposals that are the
result of activities pursuant to criteria in this subsection J, other equivalent on- or off-site
compensation to achieve no net loss of riparian function is provided.
(b) When Type Ns streams, as deflned in subsection G7 of this Section, are proposed for
relocation due to expansions of public roads or other public facility improvements pursuant to
this subsection J, the buffer area between the facility and the relocated stream shall not be less
than the width prior to the relocation. The provided buffer between the facility and the relocated
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stream shall be enhanced or improved to provide appropriate functions given the class and
condition of the stream; or if there is no buffer currently, other equivalent on- or off-site
compensation to achieve no net loss of riparian functions is provided.
(c) Applicable mitigation criteria of subsection L of this Section must be met.
(d) Proper notiflcation to the City must be made and records provided to the City of stream
relocations, pursuant to subsection D of this Section, in cases where the stream/lake is subject
to fiood hazard area regulations of this Section.
3. Criteria for Modifying Wellhead Protection Area Standards: The Department will consider modiflcation
applications in the following cases:
a. The request is to flnd that a standard is inapplicable to that activity, facility, or development permit
due to the applicant’s proposed methods or location; or
b. The request is to modify a speciflc standard or regulation due to practical difficulties; and
c. The request meets the intent and purpose of the Wellhead Protection Area regulations.
Based upon application of the tests in subsections J3a, b, and c of this Section, applications which are
considered appropriate for review as modiflcations are subject to the procedures and criteria in RMC 4-
9-250D, Modiflcation Procedures. Requests to modify regulations or standards which do not meet the
above tests shall be processed as variances.
d. The request, in addition to meeting the criteria of RMC 4-9-250D, Modiflcation Procedures, must be
based on consideration of the best available science as described in WAC 365-195-905; or where there
is an absence of valid scientiflc information, the steps in RMC 4-9-250F are followed.
4. Criteria for Approving Wetland Alterations: Wetland alterations may only be authorized after the City
makes a written flnding that the proposal is consistent with the following criteria:
a. No Net Loss: Activities that adversely affect wetlands and/or wetland buffers shall include mitigation
sufficient to achieve no net loss of wetland function and acreage and to achieve, where practicable, a
net resource gain in wetlands over present conditions. The concept of “no net loss” means to create,
restore and/or enhance a wetland so that there is no reduction to total wetland acreage and/or function.
b. Compensation for wetland alterations shall occur in the following order of preference:
i. Re-establishing wetlands on upland sites that were formerly wetlands.
ii. Rehabilitating wetlands for the purposes of repairing or restoring natural and/or historic
functions.
iii. Creating wetlands on disturbed upland sites such as those consisting primarily of nonnative,
invasive plant species.
iv. Enhancing signiflcantly degraded wetlands.
v. Preserving Category I or II wetlands that are under imminent threat; provided, that preservation
shall only be allowed in combination with other forms of mitigation and when the Administrator
determines that the overall mitigation package fully replaces the functions and values lost due to
development.
vi. Cooperative compensation to mitigation banks or in-lieu fee programs, as indicated in
subsection G9e of this Section.
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c. Mitigation Ratios for Wetland Impacts: Compensatory mitigation for wetland alterations shall be
based on the wetland category and the type of mitigation activity proposed. The replacement ratio shall
be determined according to the ratios provided in the table(s) below. The created, re-established,
rehabilitated, preserved, or enhanced wetland area shall at a minimum provide a level of functions
equivalent to the wetland being altered and shall be located in an appropriate landscape setting.
Wetland Mitigation Type and Replacement Ratio*
Wetland Category** Creation or Re-
establishment Rehabilitation Preservation Enhancement Only
Category IV 1.5:1*** 2:13:1 6:1 3:16:1
Category III 2:1 3:14:1 8:1 4:18:1
Category II 3:1 4:16:1 12:1 12:16:1
Category I 6:14:1 8:1 16:1 Not allowed 16:1
Combined Wetland Mitigation Type and Compensation Ratios*
Wetland Category** Re-establishment or
Creation (R/C) Plus
Rehabilitation (RH)
Re-establishment or
Creation (R/C) Plus
Preservation (P)****
Re-establishment or
Creation (R/C) Plus
Preservation (P)1
Category IV 1:1 R/C plus 1:1RH*** 1:1 R/C plus 2:1 P 1:1 R/C plus 2:1 E
Category III 1:1 R/C plus 2:1 RH 1:1 R/C plus 4:1 P 1:1 R/C plus 4:1 E
Category II 1:1 R/C plus 4:1 RH 1:1 R/C plus 8:1 P 1:1 R/C plus 8:1 E
Category I 1:1 R/C plus 6:1 RH 1:1 R/C plus 12:1 P 1:1 R/C plus 12:1 E
*Ratio is the replacement area: impact area.
**As deflned in RMC 4-3-050G.
***These ratios do not apply to impacts to wetlands with special characteristics.
****Consistent with Wetland Mitigation in Washington State, Part 1: Agency Policies and Guidance, Version 2
(Ecology Publication No. 21-06-003, April 2021).
d. Mitigation Ratios for Wetland Buffer Impacts: Compensation for wetland buffer impacts shall occur
at a minimum one to one (1:1) ratio. Compensatory mitigation for buffer impacts shall include
enhancement of degraded buffers by planting native species, removing structures and impervious
surfaces within buffers, and other measures.
e. Special Requirements for Mitigation Banks: Mitigation banks shall not be subject to the
replacement ratios outlined in the replacement ratio table above, but shall be determined as part of the
mitigation banking agreement and certiflcation process.
f. Buffer Requirements for Replacement Wetlands: Replacement wetlands established pursuant to
these mitigation provisions shall have adequate buffers to ensure their protection and sustainability. The
buffer shall be based on the category in subsection G2 of this Section.
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g. Location: Compensatory mitigation shall be provided on site or off site in the location that will provide
the greatest ecological beneflt and have the greatest likelihood of success. Mitigation shall occur as
close as possible to the impact area, within the same watershed sub-basin, and in a similar habitat type
as the permitted alteration unless the applicant demonstrates to the satisfaction of the Administrator
through a watershed- or landscaped-based analysis that mitigation within an alternative sub-basin of
the same watershed would have greater ecological beneflt.
h. Protection: All mitigation areas whether on or off site shall be permanently protected and managed to
prevent degradation and ensure protection of critical area functions and values into perpetuity.
Permanent protection shall be achieved through protective covenant in accordance with this Section.
5. Alterations within Flood Hazard Area:
a. Changes to Special Flood Hazard Area:
i. If a project will alter the BFE or boundaries of the special fiood hazard area, then the project
proponent shall provide the community with engineering documentation and analysis regarding the
proposed change. If the change to the BFE or boundaries of the special fiood hazard area would
normally require a FEMA Letter of Map Change, then the project proponent shall initiate, and
receive approval of, a FEMA Conditional Letter of Map Revision (CLOMR) prior to approval of the
development permit. The project shall be constructed in a manner consistent with the approved
CLOMR.
ii. If a CLOMR application is made, then the project proponent shall also supply the full CLOMR
documentation package to the Floodplain Administrator to be attached to the fioodplain
development permit, including all required property owner notiflcations.
b. Notiflcation to Other Entities: Whenever a watercourse is to be altered or relocated:
i. Notify adjacent communities and the Department of Ecology prior to such alteration or relocation
of a watercourse, and submit evidence of such notiflcation to the Federal Insurance Administrator
through appropriate notiflcation means, and
ii. Assure that the fiood carrying capacity of the altered or relocated portion of said watercourse is
maintained. (Ord. 5977, 8-10-2020)
4-3-050K VARIANCES:
See RMC 4-9-250.
4-3-050L MITIGATION, MAINTENANCE AND MONITORING:
1. Mitigation Plan Required:
a. Criteria: Mitigation plans required through the application of subsections G4 to G9 of this Section
shall comply with chapter 4-8 RMC. In addition, the applicant shall:
i. Demonstrate sufficient scientiflc expertise, the supervisory capability, and the flnancial resources
to carry out the mitigation project; and
ii. Demonstrate the capability for monitoring the site and making corrections during the monitoring
period if the mitigation project fails to meet projected goals; and
iii. Protect and manage, or provide for the protection and management, of the mitigation area to
avoid further development or degradation and to provide for long-term environmental health of the
mitigation area; and
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iv. Provide for project monitoring and allow City inspections on a schedule determined by the City;
and
v. Avoid mitigation proposals that would result in additional future mitigation or regulatory
requirements for adjacent or abutting properties.
b. Mitigation Sequencing: If alterations to critical areas are proposed for a non-exempt activity, the
applicant shall evaluate alternative methods of developing the property using the following criteria in
this order and provide reasons why a less intrusive method of development is not feasible. In
determining whether to grant permit approval pursuant to RMC 4-3-050C, a determination shall be made
as to whether the feasibility of less intrusive methods of development has been adequately evaluated
and that less intrusive methods of development are not feasible.
i. Avoiding the impact altogether by not taking a certain action or parts of an action (usually by either
flnding another site or changing the location on the site).
ii. Minimizing adverse impacts by limiting the magnitude of the action and its implementation, by
using appropriate technology, or by taking affirmative steps, such as project redesign, relocation, or
timing, to avoid or reduce impacts.
iii. Rectifying adverse impacts to wetlands, Wellhead Protection Areas, fiood hazard areas, and
habitat conservation areas by repairing, rehabilitating, or restoring the affected environment to the
historical conditions or the conditions existing at the time of the initiation of the project.
iv. Minimizing or eliminating the hazard by restoring or stabilizing the hazard area through
engineered or other methods.
v. Reducing or eliminating the adverse impacts or hazard over time by preservation and
maintenance operations over the life of the action.
vi. Compensating for adverse impacts to wetlands, Wellhead Protection Areas, fiood hazard areas,
and habitat conservation areas by replacing, enhancing, or providing substitute resources or
environments.
vii. Monitoring the hazard or other required mitigation and taking remedial action when necessary.
c. Based on Best Available Science: The applicant shall demonstrate that the mitigation is based on
consideration of the best available science as described in WAC 365-195-905; or where there is an
absence of valid scientiflc information, the steps in RMC 4-9-250F are followed.
d. Mitigation Alternatives and Location:
i. On-Site Mitigation: Mitigation shall be provided on site, unless on-site mitigation is not
scientiflcally feasible due to physical features of the property. The burden of proof shall be on the
applicant to demonstrate that mitigation cannot be provided on site.
ii. Off-Site Mitigation: When mitigation cannot be provided on site, mitigation shall be provided in
the immediate vicinity of the permitted activity on property owned or controlled by the applicant,
and identifled as such through a recorded document such as an easement or covenant, provided
such mitigation is beneflcial to the habitat area and associated resources.
iii. In-Kind Mitigation: In-kind mitigation shall be provided except when the applicant demonstrates
and the City concurs that greater functional and habitat value can be achieved through out-of-kind
mitigation.
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e. Timing of Mitigation Plan – Final Submittal and Mitigation Commencement: When a mitigation
plan is required, the proponent shall submit a flnal mitigation plan for the approval of the Administrator
prior to the issuance of building or construction permits for development. The proponent shall receive
written approval of the mitigation plan prior to commencement of any construction activity. Where the
City requires increased buffers rather than standard buffers, it shall be noted on the subdivision plan
and/or site plan.
f. Timing of Construction and/or Building Permit Issuance: In order to ensure no loss of critical area
functions and values, development permits shall not be issued prior to installation and acceptance of all
required mitigation unless a surety device in an amount of three hundred percent (300%) of the
mitigation installation contract amount is provided to the satisfaction of the City. Mitigation activities
shall be timed to occur in the appropriate season based on weather and moisture conditions.
g. When Stream or Lake Mitigation Plan Is Required: The applicant shall be required to conduct a
stream or lake mitigation plan pursuant to RMC 4-8-120 if impacts are identifled within a stream or lake
study. The approval of the stream or lake mitigation plan by the Administrator shall be based on the
following criteria.
i. Mitigation Location: Mitigation location shall follow the preferences in this subsection L:
(a) On-Site Mitigation: On-site mitigation is required unless a flnding is made that on-site
mitigation is not feasible or desirable;
(b) Off-Site Mitigation within Same Drainage Subbasin as Subject Site: Off-site mitigation
may be allowed when located within the same drainage subbasin as the subject site and if it
achieves equal or improved ecological functions over mitigation on the subject site;
(c) Off-Site Mitigation within Same Drainage Basin within City Limits: Off-site mitigation may
be allowed when located within the same drainage basin within the Renton City limits if it
achieves equal or improved ecological functions within the City over mitigation within the same
drainage subbasin as the project;
(d) Off-Site Mitigation within the Same Drainage Basin Outside the City Limits: Off-site
mitigation may be allowed when located within the same drainage basin outside the Renton City
limits if it achieves equal or improved ecological functions over mitigation within the same
drainage basin within the Renton City limits and it meets City goals.
ii. Mitigation Type: In all cases, mitigation shall provide for equivalent or greater biological
functions pursuant to subsection L1giii(a) of this Section. Additionally, there shall be no net loss of
riparian area or shoreline ecological function resulting from any activity or land use occurring within
the regulated buffer area. Types of mitigation shall follow the preferences in this subsection L:
(a) Daylighting (returning to open channel) of streams or removal of manmade salmonid
migration barriers;
(b) Removal of impervious surfaces in buffer areas and improved biological function of the
buffer;
(c) In-stream or in-lake mitigation as part of an approved watershed basin restoration project;
(d) Other mitigation suitable for site and water body conditions that meet all other provisions for
a mitigation plan.
iii. Contiguous Corridors: Mitigation sites shall be located to preserve or achieve contiguous
riparian or wildlife corridors to minimize the isolating effects of development on habitat areas, so
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long as mitigation of aquatic habitat is located within the same aquatic ecosystem as the area
disturbed.
(a) Equivalent or Greater Biological Functions: The Administrator shall utilize the report “City
of Renton Best Available Science Literature Review and Stream Buffer Recommendations” by
AC Kindig and Company and Cedarock Consultants, dated February 27, 2003, unless
superseded with a City-adopted study, to determine the existing or potential ecological function
of the stream or lake or riparian habitat that is being affected. Alternate reports or literature that
meet Best Available Science may be utilized as supplemental information in order to ensure the
Administrator’s determination refiects current science and analysis. Mitigation shall address
each function affected by the alteration. Mitigation to compensate alterations to stream/lake
areas and associated buffers shall achieve equivalent or greater biologic and hydrologic
functions and shall include mitigation for adverse impacts upstream or downstream of the
development proposal site. No net loss of riparian habitat or water body function shall be
demonstrated.
(b) Minimum Mitigation Plan Performance Standards: See subsection L1 of this Section.
iv. Alternative Mitigation: The mitigation requirements set forth in this subsection L1 may be
modifled at the Administrator’s discretion if the applicant demonstrates that improved habitat
functions, on a per-function basis, can be obtained in the affected sub-drainage basin as a result of
alternative mitigation measures.
2. Surety Devices:
a. Required for Mitigation Plans: For any mitigation plans required as a result of the application of
these regulations, a surety device shall be required to ensure performance consistent with RMC 4-1-
230. The King County Critical Areas Mitigation Bond Quantity Worksheet may be used by applicants to
determine appropriate amounts sufficient to cover the cost of conformance with the conditions of this
Section, including corrective measures associated with work that is not completed. After the
Administrator determines that mitigation has been successfully completed in compliance with the
approved mitigation plan and the monitoring period has expired, the surety device shall be released. The
City may collect against the surety device and require the property owner to sign a property access
release form when work, which is not completed, is found to be in violation of the conditions set forth in
the mitigation plan and/or the Administrator determines that the site is in violation of the purposes of
this Section.
b. Time Period: The surety device shall be sufficient to guarantee that structures, improvements, and
mitigation required by permit condition perform satisfactorily for a minimum of flve (5) years after they
have been completed.
3. Monitoring: All compensatory mitigation projects shall be monitored for a period necessary to establish
that performance standards have been met, but generally not for a period less than flve (5) years. Reports for
wetland mitigation projects shall be submitted quarterly for the flrst year and thereafter annually for the next
four (4) years following construction for a total of flve (5) years minimum. Subsequent reporting shall be
required if applicable to document milestones, successes, problems, and contingency actions of the
compensatory mitigation. Should the mitigation project fail to meet established success criteria at any point,
the monitoring period shall be started over at year one. The Administrator shall have the authority to modify
or extend the monitoring period and require additional monitoring reports for up to ten (10) years when any of
the following conditions apply:
a. The project does not meet the performance standards identifled in the mitigation plan;
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b. The project does not provide adequate replacement for the functions and values of the impacted
critical area;
c. The project involves establishment of forested plant communities, which require longer time for
establishment.
4-3-050M APPEALS:
1. General: See RMC 4-8-070, Authority and Responsibilities, and RMC 4-8-110.
2. Record Required – Flood Hazard Areas: See RMC 4-9-250B.
4-3-050N UNAUTHORIZED ALTERATIONS AND ENFORCEMENT:
1. Stop Work Order: When a critical area or its buffer has been altered in violation of this Title, all ongoing
development work shall stop. The City shall have the authority to issue a stop work order to cease all ongoing
development work, and order restoration, rehabilitation, or replacement measures at the owner’s or other
responsible party’s expense to compensate for violation of provisions of this Title.
2. Requirement and Timing for Restoration Plan and Site Restoration: All development work shall remain
stopped until a restoration plan is prepared and approved by City. Such a plan shall be prepared by a
qualifled professional using the best available science and shall describe how the actions proposed meet the
minimum requirements described in subsection N3 of this Section. The Administrator shall, at the violator’s
expense, seek expert advice in determining the adequacy of the plan. Inadequate plans shall be returned to
the applicant or violator for revision and resubmittal. Once the restoration plan has been approved by the
City, the applicant must implement the plan to the satisfaction of the City prior to recommencing
development activity.
3. Minimum Performance Standards for Restoration: Information demonstrating compliance with the
requirements in subsection L of this Section shall be submitted to the Administrator. The following minimum
performance standards shall be met for the restoration of a critical area; provided, that if the violator can
demonstrate that greater functional and habitat values can be obtained, these standards may be modifled:
a. Wellhead Protection Areas, Flood Hazard Areas, Wetlands, and Habitat Conservation Areas:
i. The historic structural and functional values shall be restored, including water quality and habitat
functions;
ii. The historic soil types and conflguration shall be replicated;
iii. The critical area and buffers shall be replanted with native vegetation that replicates the
vegetation historically found on the site in species types, sizes, and densities. The historic functions
and values should be replicated at the location of the alteration; and
b. Geologic Hazards:
i. The hazard shall be reduced to a level equal to, or less than, the pre-development hazard; and
ii. Any rRisk of personal injury resulting from the alteration shall be eliminated or minimized; and
iii. The hazard area and buffers shall be replanted with native vegetation sufficient to minimize the
hazard.
4. Site Investigations Authorized: The Administrator is authorized to make site inspections and take such
actions as are necessary to enforce this Title. The Administrator shall present proper credentials and make a
reasonable effort to contact any property owner before entering onto private property.
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5. Penalties: See RMC 4-3-120 and chapter 4-1 RMC. (Ord. 5757, 6-1-2015)
4-11-040 DEFINITIONS D:
A. DANCE CLUB: Any facility, restricted to adults over twenty-one (21) years of age, at which dancing occurs,
as a primary form of entertainment. This deflnition excludes adult entertainment businesses, entertainment
clubs, and gaming/gambling facilities, dance halls and other establishments conducting public dances as
deflned in RMC 5-13-1.
B. DANCE HALL: Any place where a public dance, as deflned in RMC 5-13-1, is conducted without restriction
on age, or restricted to minors only. Dance halls are further regulated under RMC Title 5 and require a license
to operate. This deflnition excludes adult entertainment businesses, dance clubs, entertainment clubs, and
gaming/gambling facilities.
C. DANGEROUS BUILDING: As deflned by the “Uniform Code for the Abatement of Dangerous Buildings.”
D. DATA CENTER: A facility used primarily for off-site storage of computer systems and associated
components including applications and secure data. Some data centers may include maintenance areas and
a small office. Data centers may be occupied by single or multiple tenants, but typically have a small number
of employees and visitors. See RMC 4-11-230, WAREHOUSING.
E. DAY CARE CENTER: A day care operation licensed by the State of Washington (WAC 388-73-014), for
thirteen (13) or more children in any twenty-four (24) hour period, or any number of children in a
nonresidential structure. This deflnition does not include adult day care/health.
F. DAY CARE, FAMILY, HOME: A day care operation licensed by the State of Washington (WAC 388-73-014),
caring for twelve (12) or fewer children in any twenty-four (24) hour period within the caregiver’s place of
residence.
G. DAYLIGHTING: Restoration of a culverted or buried watercourse to a surface watercourse.
H. DEDICATION: A deliberate appropriation of land by its owner for any general and public uses, reserving to
himself/herself no other rights than such as are compatible with the full exercises and enjoyment of the
public uses to which the property has been devoted.
I. DEED OF DEDICATION: A formal dedication of right-of-way or easement to the City, to be approved by City
Council, the Hearing Examiner, the Public Works Administrator or designee, or the Community and Economic
Development Administrator or designee.
J. DEMOLITION WASTE: Solid waste resulting from the demolition or razing of buildings, roads and other
human-made structures. Demolition waste includes, but is not limited to, concrete, brick, bituminous
concrete, wood and masonry, composition rooflng and rooflng paper, steel, and minor amounts of other
metals like copper.
K. DENSITY, GROSS: A measure of population, dwelling units, number of lots, or building area related to land
area, and expressed as a ratio, i.e., one thousand (1,000) people per square mile, one (1) dwelling unit per
acre, or one (1) lot per acre.
L. DENSITY, NET: A calculation of the number of housing units and/or lots that would be allowed on a
property after critical areas, i.e., very high landslide hazard areas, protected slopes (except evaluate on a
case-by-case basis those protected slopes created by previous development), wetlands, Class F, Np and Ns
water bodiesClass 1 to 4 streams and lakes, or fioodways, and public rights-of-way and legally recorded
private access easements, are subtracted from the gross area (gross acres minus streets and critical areas
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multiplied by allowable housing units per acre). Developments meeting the deflnition of a shopping center
are not required to deduct areas within access easements from the gross site area for the purpose of
calculating net density. Required critical area buffers, streams that have been daylighted including restored
riparian and aquatic areas, public and private alleys, unit lot drives, drives, joint use driveways (and the
access easements upon them), and trails shall not be subtracted from gross acres for the purpose of net
density calculations. All fractions which result from net density calculations shall be truncated at two (2)
numbers past the decimal (e.g., 4.5678 becomes 4.56). Calculations for minimum or maximum density
which result in a fraction that is one-half (0.50) or greater shall be rounded up to the nearest whole number.
Those density calculations resulting in a fraction that is less than one-half (0.50) shall be rounded down to the
nearest whole number.
M. DEPARTMENT: The Department of Community and Economic Development of the City of Renton, unless
otherwise specifled.
N. DEPARTMENT ADMINISTRATOR: See ADMINISTRATOR.
O. DEPOSIT AREA: The designated area(s) where refuse, recyclables, and compostables will be stored.
P. DESIGNATED ZONE FACILITY: Any hazardous waste treatment and storage facility that requires an interim
or flnal status permit under rules adopted under chapter 70.105 RCW and that is not a “preempted facility” as
deflned in RCW 70.105.010.
Q. DETENTION/RETENTION FACILITIES: Facilities designed either to hold runoff for a short period of time
and then release it to the point of discharge at a controlled rate or to hold water for a considerable length of
time during which the volume is reduced through evaporation, evapotranspiration by plants, or inflltration into
the ground.
R. DETERMINATION OF NONSIGNIFICANCE (DNS): The written decision by the responsible official of the
lead agency that a proposal is not likely to have a signiflcant adverse environmental impact, and therefore an
EIS is not required (WAC 197-11-310 and 197-11-340). The DNS form is in WAC 197-11-970.
S. DETERMINATION OF NONSIGNIFICANCE, MITIGATED (MDNS): A DNS that includes mitigation measures
and is issued as a result of the process specifled in WAC 197-11-350.
T. DETERMINATION OF SIGNIFICANCE (DS): The written decision by the responsible official of the lead
agency that a proposal is likely to have a signiflcant adverse environmental impact, and therefore an EIS is
required (WAC 197-11-310 and 197-11-360). The DS form is in WAC 197-11-980 and must be used
substantially in that form.
U. DEVELOPABLE AREA: Land area outside of critical areas, critical area and shoreline buffers, and public
rights-of-way that is otherwise developable.
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V. DEVELOPMENT: The division of a parcel of land into two (2) or more parcels; the construction,
reconstruction, conversion, structural alteration, relocation or enlargement of any structure; any mining,
excavation, landflll or land disturbance and any use or extension of the use of land.
W. DEVELOPMENT: (This deflnition for RMC 4-3-050, Critical Areas Regulations, use only.) Any manmade
change to improved or unimproved real estate, including but not limited to buildings or other structures,
mining, dredging, fllling, grading, paving, excavation or drilling operations or storage of equipment or
materials located within the area of special fiood hazard.
X. DEVELOPMENT: (This deflnition for RMC 4-3-090, Shoreline Master Program Regulations, use only.) A use
consisting of the construction or exterior alteration of structures; dredging; drilling; dumping; fllling; removal
of any sand, gravel or minerals; bulkheading; driving of piling; placing of obstructions; or any other projects of
a permanent or temporary nature which interferes with the normal public use of the surface of the waters
overlying lands subject to the Act at any state of water level. This does not include dismantling or removing
structures if there is no other associated development or redevelopment.
Y. DEVELOPMENT AGREEMENT: A recorded contract entered into by the city and an applicant setting forth
development standards and other provisions governing and vesting a development or use for a duration of
time specifled in the contract. May be used to obligate an applicant to fund or provide services,
infrastructure, or other facilities.
Z. DEVELOPMENT PERMIT: Written permission after appropriate review for type of application from the
appropriate decision-maker authorizing the division of a parcel of land, the construction, reconstruction,
conversion, structural alteration, relocation or enlargement of any structure, utility, or any use or extension of
the use of the land.
AA. DEVELOPMENT REGULATIONS (for vesting purposes): The following controls placed on development
or land use activities by the City, including but not limited to: Comprehensive Plan Policies, zoning
regulations, subdivision regulations, shoreline management regulations, road design standards, site
development regulations, sign regulations, critical areas regulations, and all regulations and land use
controls that must be satisfled as a prerequisite to obtaining approval of an application for development. For
the purposes of this deflnition, construction and utility regulations such as stormwater standards and
erosion/sediment control requirements contained in RMC Title IV, Development Regulations, building
standards, flre standards, sewer utility standards, and Health Department standards are not considered
development regulations or land use controls. RMC Title IV processes and procedures are not considered
development regulations or land use controls.
BB. DEVELOPMENT SERVICES DIRECTOR: The Director of the Development Services Division of the
Department of Community and Economic Development or designee.
CC. DISPLAY SURFACE: The area made available by the sign structure for the purpose of displaying the
advertising message.
DD. DISPLAY WINDOW: A window in a building facade intended for nonpermanent display of goods and
merchandise.
EE. DIVERSION FACILITY: A facility that provides inpatient healthcare for individuals that are self-admitted or
ordered, diverted, or referred from jails, hospitals, doctors or similar treatment facilities or professionals, or
by flrst responders, including law enforcement, hospital emergency department social workers, and similar
professionals. Services may include an array of inpatient healthcare treatment and support services
including but not limited to screening and assessment, psychological counseling, case management, crisis
management, detox services, substance use and trauma-related treatment services, behavioral/mental
health care, medical isolation, care, or treatment, counseling, respite services, and various levels of
accommodations for sleeping purposes. Some outpatient healthcare services may be provided. Not included
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in this deflnition are congregate residences, assisted living facilities, adult family homes, group homes,
convalescent centers, social service organizations, or homeless services uses.
FF. DOCK: A flxed or fioating platform extending from the shore over the water.
GG. DOUBLE CHECK VALVE ASSEMBLY: See RMC 4-6-100.
HH. DOUBLE-WALLED: See RMC 4-5-120G.
II. DOWNTOWN BUSINESS DISTRICT: Those uses, buildings, and walkways within the area mapped in
RMC 4-2-080D. In general, the area is bounded at the north by parcel lines near South Second Street, at the
east by the Cedar River and I-405, at the south by parcel lines near South Fourth Street and parcel lines along
South Third Street, and at the west by parcels along Burnett Avenue South and Shattuck Avenue South.
JJ. DRAINAGE AREA: The total area whose drainage water fiows to and across the subject property.
KK. DREDGING: The removal of earth from the bottom or banks of a body of water.
LL. DRIP LINE: A tree’s drip line shall be described by a line projected to the ground from the outer edge of the
tree canopy delineating the outermost extent of foliage in all directions.
MM. DRIP LINE, PROTECTED: A tree drip line identifled to be retained and preserved as an undisturbed,
vegetated area that fully encompasses the drip line of a protected tree removed in violation of a land
development permit.
NN. DRIVE-IN/DRIVE-THROUGH RETAIL OR SERVICE: A business or a portion of a business where a
customer is permitted or encouraged, either by the design of physical facilities or by service and/or packaging
procedures, to carry on business in the off-street parking or paved area accessory to the business, while
seated in a motor vehicle. In some instances, customers may need to get out of the vehicle to obtain the
product or service. This deflnition shall include but not be limited to drive-in/drive-through services at eating
and drinking establishments, fast-food restaurants, coffee stands, and banks and pharmacies. This deflnition
excludes vehicle service and repair, vehicle fueling stations, and car washes.
OO. DRIVEWAY, SHARED: A single driveway serving two (2) or more adjoining lots, parcels, or tracts for the
purposes of vehicular access. New shared driveways shall conform to the provisions of RMC 4-6-060J,
Shared Driveway Standards.
PP. DROP-OFF ZONE: A sidewalk area abutting a street intended for passengers to enter or exit vehicles that
are temporarily parked for that purpose.
QQ. DWELLING, ATTACHED: A dwelling unit connected to one (1) or more dwellings by common roofs, walls,
or fioors or a dwelling unit or units attached to garages or other nonresidential uses. This deflnition includes
all structures or portions of structures meeting this deflnition, but excludes boarding and lodging houses,
adult family homes, and group home I or group home II, as deflned herein.
RR. DWELLING, DETACHED: A building containing one (1) dwelling unit which is not attached to any other
dwelling by any means except fences and is surrounded by open space or yards. This deflnition includes
single-family dwellings and cottages.
SS. DWELLING UNIT: A structure or portion of a structure designed, occupied, or intended for occupancy as
a single residential unit providing complete, independent living facilities with separated living quarters, a
kitchen, sleeping, and sanitary facilities provided for the exclusive use of a single household. For the
purposes of this deflnition, “sanitary facilities” shall include a sink, a toilet, and a shower or bathtub. Dwelling
units (attached or detached) include the following types:
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1. Apartment(s): Multiple attached dwelling units in a residential building in which units may be separately
rented or owned. Unit entrances are provided from a common internal corridor and individual units’ habitable
area is provided on a single level.
2. Accessory Dwelling Unit(s): An independent subordinate dwelling unit that is located on the same lot as a
single-family dwelling, courtyard apartment, stacked fiat, duplex, triplex, fourplex, and/or townhouse, or on
the same lot as a principal building actively operated with a nonresidential use by a religious institution or
social service organization. This may include units over detached garages.
3. Cottage(s): A detached, single-family dwelling unit that is oriented around a shared common open space
within a unit lot subdivision.
4. Courtyard Apartment(s): Attached dwelling units arranged on two (2) or three (3) sides of a yard or court.
5. Garden Style Apartment(s): A dwelling unit that is one (1) of several stacked vertically, with exterior
stairways and/or exterior corridors and surface parking. Parking is not structured and may include detached
carports or garages. Buildings and building entries are oriented toward internal drive aisles and/or parking lots
and not street frontage. There is typically no formal building entry area connected to a public sidewalk and a
public street.
6. Middle Housing: Attached dwelling units that are compatible in scale, form, and character with single-
family dwellings, having a permanent foundation, and containing two or more attached or stacked homes,
including duplexes, triplexes, fourplexes, townhouses, stacked fiats, and courtyard apartments.
7. Single-Family: A detached dwelling unit which is not attached to any other dwelling unit(s) by any means
except fences, has a permanent foundation, and is surrounded by open space or yards. This deflnition does
not include accessory dwelling units or manufactured homes.
8. Townhouse(s): A dwelling unit attached to one (1) or more such units by one (1) or more common vertical
walls in which each unit occupies the building from the bottom of the foundation to the roof, has at least two
(2) exterior faces, front and rear ground-level access to the outside, and no unit is located over another unit.
Townhouse units may be multistory.
(Ord. 2520, 11-17-1969; Ord. 2698, 3-6-1972; Ord. 3891, 2-25-1985; Ord. 4346, 3-9-1992; Ord. 4351, 5-4-1992;
Ord. 4367, 9-14-1992; Ord. 4466, 8-22-1994; Ord. 4521, 6-5-1995; Ord. 4522, 6-5-1995; Ord. 4637, 9-14-1992;
Ord. 4671, 7-21-1997; Ord. 4716, 4-13-1998; Ord. 4773, 3-22-1999; Ord. 4835, 3-27-2000; Ord. 4851, 8-7-
2000; Amd. Ord. 4963, 5-13-2002; Ord. 4999, 1-13-2003; Ord. 5100, 11-1-2004; Ord. 5124, 2-7-2005; Ord.
5137, 4-25-2005; Ord. 5192, 1-23-2006; Ord. 5286, 5-14-2007; Ord. 5387, 6-9-2008; Ord. 5392, 6-23-2008;
Ord. 5473, 7-13-2009; Ord. 5474, 7-13-2009; Ord. 5520, 12-14-2009; Ord. 5577, 11-15-2010; Ord. 5607, 6-6-
2011; Ord. 5648, 12-12-2011; Ord. 5650, 12-12-2011; Ord. 5675, 12-3-2012; Ord. 5676, 12-3-2012; Ord. 5749,
1-12-2015; Ord. 5757, 6-1-2015; Ord. 5804, 5-23-2016; Ord. 5818, 10-17-2016; Ord. 5867, 12-11-2017; Ord.
5899, 11-19-2018; Ord. 5958, 12-9-2019; Ord. 5976, 8-3-2020; Ord. 5996, 12-14-2020; Ord. 6000, 12-14-2020;
Ord. 6019, 6-14-2021; Ord. 6026, 9-20-2021; Ord. 6046, 12-13-2021; Ord. 6068, 6-13-2022; Ord. 6076, 8-8-
2022; Ord. 6100, 12-5-2022; Ord. 6102, 12-12-2022; Ord. 6127, 12-11-2023; Ord. 6128, 12-11-2023; Ord. 6160
(Exh. G), 6-16-2025)
4-11-190 DEFINITIONS S:
A. SALES/MARKETING TRAILERS, ON-SITE: Trailers used for temporary on-site sales and marketing of
developments and/or construction sites.
B. SALMONID MIGRATION BARRIER: An in-stream blockage that consists of a natural drop (no human
infiuence) with an uninterrupted slope greater than one hundred percent (100%) (forty flve (45) degree angle)
and a height in excess of eleven (11) vertical feet within anadromous salmon-bearing waters or a height in
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excess of three (3) vertical feet within resident trout-only bearing waters. Human-made barriers to salmonid
migration (e.g., culverts, weirs, etc.) shall be considered barriers to salmonid migration by this deflnition, only
if they were lawfully installed; permanent; present a complete barrier to salmonid passage based on
hydraulic drop, water velocity, water depth, or any other feature which would prevent all salmonids from
passing upstream; and in the opinion of the Community and Economic Development Administrator cannot be
modifled to provide salmonid passage without resulting in signiflcant impacts to other environmental
resources, major transportation and utility systems, or to the public, and would have signiflcant expense. For
the purposes of this deflnition, “signiflcant expense” means a cost equal to or greater than flfty percent (50%)
of the combined value of the proposed site buildings, structures, and/or site improvements, and existing
buildings, structures, and/or site improvements to be retained.
C. SCHOOLS/STUDIOS, ARTS AND CRAFTS: Schools and studios for education in various arts and crafts
including but not limited to photography, dance, music, and language skills.
D. SCOUR: The erosive action of running water in streams, which excavates and carries away material from
the bed and banks. Scour may occur in both earth and solid rock material.
E. SECONDARY CONTAINMENT: See RMC 4-5-120G.
F. SECURE COMMUNITY TRANSITION FACILITY (SCTF): A residential facility for persons civilly committed
and conditionally released to a less restrictive alternative under chapter 71.09 RCW. A secure community
transition facility has supervision and security, and either provides or ensures the provision of sex offender
treatment services. Secure community transition facilities include but are not limited to the facilities
established pursuant to RCW 71.09.250 and any community-based facilities established under
chapter 71.09 RCW and operated by or under contract with the Washington State Department of Social and
Health Services. (Ord. 4982, 9-23-2002)
G. SEGREGATION: Division of land into lots or tracts each of which is one-one hundred twenty eighth (1/128)
of a section of land or larger, or flve (5) acres or larger if the land is not capable of description as a fraction of a
section of land.
H. SENSITIVE AREAS: See CRITICAL AREAS.
I. SEPA: The State Environmental Policy Act of 1971 (chapter 43.21C RCW).
J. SERVICEABLE: Presently usable.
K. SERVICES, OFF-SITE: Establishments primarily engaged in providing individual or professional services at
the customer’s home or place of business. Examples of off-site services include, but are not limited to,
temporary employment services, janitorial services, and professional house cleaner services. This deflnition
excludes social service organizations and on-site services.
L. SERVICES, ON-SITE: Establishments primarily engaged in providing individual or professional services
within the place of business, such as beauty and barber shops, retail laundry and dry-cleaning including
coin-operated, garment alterations and repair, photo studios, shoe repair, pet grooming, real estate offices,
personal accountants, indoor rental services, and repair of personal or household items, except for vehicle
repair. This deflnition excludes adult retail uses, social service organizations, and off-site services.
M. SETBACK: The minimum required distance between the building footprint and the property line and any
private access easement or tract. For lots containing private access easements, setbacks are the minimum
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required distance between the building footprint and the easement. A setback is measured perpendicularly
from a lot line or private easement access to the outer wall of the structure. In the case where a structure
does not have an outer wall, such as a carport, the measurement shall be to the posts of such structure,
unless otherwise determined by the Department of Community and Economic Development.
N. SETBACK: (This deflnition for RMC 4-3-090, Shoreline Master Program Regulations, use only.) A required
land area specifled in the Shoreline Master Program, measured horizontally upland from and perpendicular
to the vegetation conservation buffer, within which no buildings or other permanent structures may be
constructed and that serves to protect the vegetation conservation buffer during development activities, use,
and routine maintenance of structures and improvements landward of the building setback.
O. SETBACK LINE, LEGAL: The line established by ordinance beyond which no building may be built.
P. SEWAGE: See RMC 4-6-100.
Q. SEWAGE DISPOSAL AND TREATMENT PLANTS: A facility designed for the collection, removal, treatment,
and disposal of waterborne sewage. This deflnition excludes disposal facilities.
R. SEWAGE TREATMENT PLANT: See RMC 4-6-100.
S. SEWAGE WORKS: See RMC 4-6-100.
T. SEWER: See RMC 4-6-100.
U. SEWER, BUILDING: See RMC 4-6-100.
V. SEWER, PUBLIC: See RMC 4-6-100.
W. SEWER, SANITARY: See RMC 4-6-100.
X. SHARED PARKING: Use of a parking area for more than one use.
Y. SHOPPING CENTER: A group of buildings, structures and/or uncovered commercial areas, or a single
building containing four (4) or more individual commercial establishments, planned, developed and managed
as a unit related in location and type of shops to the trade areas that the unit serves.
Z. SHORELAND or SHORELAND AREAS: Those lands extending landward for two hundred feet (200’) in all
directions, as measured on a horizontal plane from ordinary high water mark; fioodways and contiguous
fioodplain areas landward two hundred feet (200’) from such fioodways; and all marshes, bogs, swamps, and
river deltas, associated with streams, lakes and tidal waters which are subject to the provisions of the State
Shorelines Management Act. For purposes of determining jurisdictional area, the boundary will be either two
hundred feet (200’) from the ordinary high water mark, or two hundred feet (200’) from the fioodway,
whichever is greater.
AA. SHORELINE STABILIZATION: Structural and nonstructural methods to address erosion impacts to
property and dwellings, businesses, or structures caused by natural processes, such as currents, fioods,
tides, wind, or wave action.
BB. SHORELINES: All of the water areas of the State regulated by the City of Renton, including reservoirs, and
their associated shorelands, together with the lands underlying them, except:
1. Shorelines of statewide signiflcance.
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2. Shorelines on segments of streams upstream of a point where the mean annual fiow is twenty (20) cubic
feet per second or less and the wetlands associated with such upstream segments.
3. Shorelines on lakes less than twenty (20) acres in size and wetlands associated with such small lakes.
CC. SHORELINES OF STATEWIDE SIGNIFICANCE: Those shorelines described in RCW 90.58.030(2)(e).
DD. SHORELINES OF THE STATE: The total of all “shorelines” and “shorelines of statewide signiflcance”
regulated by the City of Renton.
EE. SHORT PLAT: The map or representation of a short subdivision. See PLAT, SHORT.
FF. SHORT SUBDIVISION: See PLAT, SHORT.
GG. SIDE SEWER: See RMC 4-6-100.
HH. SIDE SEWER STUB: See RMC 4-6-100.
II. SIDE YARD: See YARD REQUIREMENT.
JJ. SIDEWALK: A concrete walkway separated from the roadway by a curb, planting strip or roadway shoulder.
KK. SIGHT TRIANGLE: See CLEAR VISION AREA.
LL. SIGN: Any medium, including merchandise, its structure and component parts, that is used or intended
to be used to attract attention to the subject matter for advertising purposes. Signs do not include sculptures,
wall paintings, murals, collages, and other design features determined to be public art by the City.
MM. SIGN, A-FRAME: See SIGN, PORTABLE.
NN. SIGN, ANIMATED: A sign with action or motion, fiashing or color changes requiring electrical energy,
electronic or manufactured source of supply, but not including revolving signs or wind actuated elements
such as fiags or banners.
OO. SIGN AREA: A measurement of the total area of a sign visible from any one viewpoint or direction,
excluding the sign support structure, architectural embellishments, or, framework that contains no written
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copy, or does not form part of the sign proper or of the display. Freestanding letters or characters, where no
background is specially provided, shall be measured by determining the smallest rectangle or polygon that
encloses the extreme limits of the shapes to be used.
PP. SIGN, COMBINATION: Any sign incorporating any combination of the features of pole, projecting and roof
signs.
QQ. SIGN, ELECTRIC: Any sign containing or utilizing electrical wiring, but not including signs illuminated by
an exterior light source.
RR. SIGN, ELECTRONIC MESSAGE BOARD: Signs whose alphabetic, pictographic, or symbolic informational
content can be changed or altered on a flxed display screen composed of electrically illuminated segments.
SS. SIGN, FREESTANDING: A sign wholly supported by a sign structure in the ground.
TT. SIGN, GROUND: A type of freestanding sign, other than a freestanding pole sign, in which the sign is in
contact with or close to the ground, has a solid base anchor, and is independent of any other structure.
UU. SIGN HEIGHT: Measured as the distance from grade, unless otherwise designated, to the top of the sign
or sign structure.
VV. SIGN, ON-PREMISES: A sign which displays only advertising copy strictly incidental to the lawful use of
the premises on which it is located, including signs or sign devices indicating the business transacted at,
services rendered, goods sold or produced on the immediate premises, name of the business, person, flrm or
corporation occupying the premises.
WW. SIGN, POLITICAL: Signs advertising a candidate or candidates for public, elective office or a political
party, or signs urging a particular vote or action on a public issue decided by ballot whether partisan or
nonpartisan.
XX. SIGN, PORTABLE: A sign not permanently affixed which is designed for or capable of movement, except
for those signs explicitly designed for people to carry on their persons or which are permanently affixed to
motor vehicles.
1. Sign, A-Frame: A nonilluminated type of portable sign comprised of hinged panels conflgured in the
shape of the alphabetic letter “A.” These signs contact the ground but are not anchored to the ground and are
independent of any other structure.
YY. SIGN, PRIMARY ENTRY: A type of freestanding sign, other than a pole sign, of ten feet (10’) or less in
height, in which the sign is in contact with the ground, has a solid base anchor, and is independent of any
other structure and serves the function of directing customers to the main entrance of a multi-tenant building
or multi-building complex.
ZZ. SIGN, PROJECTING: A sign other than a wall sign which projects from and is supported by a wall or a
building or structure, and does not extend above any adjacent parapet or roof of the supporting building.
AAA. SIGN, REAL ESTATE: A sign advertising and/or directing individuals to the sale, rent or lease of
property.
1. Commercial Real Estate Banner Sign: A sign of any shape made of lightweight fabric or similar material
that is mounted to a building by any means, and indicating that the property is for sale, rent, or lease. National
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fiags, state or municipal fiags, holiday fiags, or the official fiag of any institution or business shall not be
considered banners.
2. Decorative Real Estate Flag: A portion of lightweight fabric or similar material, supported by a vertical or
horizontal staff, intended to fiutter in the wind, and is used to attract attention to any type of residential
development for sale, rent, or lease. National fiags, state or municipal fiags, holiday fiags, or the official fiag
of any institution or business shall not be considered banners.
3. Freestanding Real Estate Signs: Any type of nonilluminated freestanding sign, indicating that the
property on which it is located, is for sale, rent, or lease. This sign type includes yardarm or ground signs.
4. Open House Sign: A nonilluminated type of portable sign comprised of hinged panels conflgured in the
shape of the alphabetic letter “A,” no larger than thirty two inches wide by thirty six inches high (32" by 36")
per each sign face. The sign text for an open house sign contains the phrase: “open” or “for sale” or “for rent”
or “for lease.”
5. Real Estate Directional Sign: Any nonilluminated type of freestanding sign that provides direction to
property(ies) for sale, rent, or lease. Within the City Center Sign Regulation Boundaries (as shown in RMC 4-4-
100H3), real estate directional signs may also include portable signs comprised of hinged panels conflgured
in the shape of the alphabetic letter “A.”
6. Real Estate Sign Kiosk: A City-approved monument style sign in the public right-of-way or on private
property consolidating numerous real estate directional signs and designed to reduce sign clutter.
7. Real Estate Sign Kiosk Directional Panel: A sign affixed within an approved real estate sign kiosk
indicating direction to various real estate developments.
BBB. SIGN, ROOF: A sign erected upon or above a roof or parapet of a building or structure.
CCC. SIGN STRUCTURE: Any structure which supports or is capable of supporting any sign as deflned in
this Title. A sign structure may be a single pole and may not be an integral part of the building.
DDD. SIGN, TEMPORARY: Any sign, banner, or advertising display constructed of cloth, canvas, light fabric,
cardboard, wallboard or other light materials, with or without frames, or advertising device intended to be
displayed only for a limited period of time including the following types of signs:
1. Advertising Device: Balloons, fiags, infiatable statuary and flgures, light strings, pennants/streamers,
portable readerboards, searchlights, wind-animated devices, and similar devices of a carnival nature.
2. Balloon: A spherical, fiexible, nonporous bag infiated with air or gas lighter than air, such as helium, and
intended to fioat in the air.
3. Banner: Any sign of lightweight fabric or similar material that is mounted to a pole and/or building by any
means. National fiags, state or municipal fiags, holiday fiags, or the official fiag of any institution or business
shall not be considered banners. A banner is not deflned by shape and may be square, rectangular, round,
triangular/pennant shaped, etc.
a. Banner, Pole Hung: A banner attached at its top and bottom to a pole or light standard by extensions
from the pole.
b. Banner, Pole/Wall Strung: A banner attached at its top and bottom corners strung between buildings,
poles, and/or light standards.
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c. Banner, Wall Hung: A banner attached to a building and where the banner lies fiat against the building
surface at all times.
4. Devices of a Carnival Nature: All temporary signs, advertising devices, lights, and other means of
attracting attention, which are commonly associated with carnival settings, and which are not otherwise
speciflcally identifled in the Renton Municipal Code. Fabric or plastic bunting shall be considered one type of
carnival device.
5. Flag: A piece of cloth or plastic, supported by a vertical or horizontal staff, which is intended to fiutter in
the wind.
6. Infiatable Statuary: An advertising device that is infiated and the likeness of an animate or inanimate
object or cartoon flgure is used to attract attention, advertise, promote, market, or display goods and/or
services.
7. Manual Message Board: Any sign that is designed so that characters, letters, or illustrations can be
changed or rearranged by hand without altering the face or the surface of the sign.
8. Pennant/Streamer: An individual object and/or series of small objects made of lightweight plastic,
fabric, or other material, which may or may not contain text, which is suspended from and/or twined around a
rope, wire, or string.
9. Readerboards, Portable: A sign which is self-supporting but not permanently attached to the ground or
building and can be moved from one location to another and is typically internally illuminated. Portable
readerboards are also known as “trailer signs.”
10. Sign, Rigid Portable: A sign which is not permanently affixed and designed for or capable of movement.
Those signs explicitly designed for people to carry on their persons or which are permanently affixed to motor
vehicles are considered to be rigid portable signs. A rigid portable sign is not considered to be a portable
readerboard or “trailer sign.”
11. Sign, Window: Any sign, temporary or permanent, designed to communicate information about an
activity, business, commodity, event, sale, or service, that is placed inside a window. Interior display of
merchandise for sale, including accessory mannequins and other props, shall not be considered window
signs.
12. Wind-Animated Object: Any device, e.g., windsocks, pinwheels, whirligigs, etc., whose primary
movements are caused by the wind or atmospheric conditions, attached by a tether. A balloon or infiatable
statuary, with or without movable parts, is not considered a wind-animated object.
EEE. SIGN, TRADITIONAL MARQUEE: A sign typically associated with movie theaters, performing arts
theaters, and theatrical playhouses. The sign is attached fiat against and parallel to the surface of a marquee
structure. In addition, a changeable copy area is included where characters, letters, or illustrations can be
changed or rearranged without altering the face or the surface of the sign.
FFF. SIGN, UNDER MARQUEE: A lighted or unlighted display attached to the underside of a marquee
protruding over public or private sidewalks. Under marquee signs may also be called “under awning” or
“under canopy” signs.
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GGG. SIGN, WALL: Any sign painted, attached or erected against the wall of a building or structure, with the
exposed face of the sign in a plane parallel to the plane of said wall. In order to be considered a wall sign, a
sign may not extend above any adjacent parapet or the roof of the supporting building.
HHH. SIGNIFICANT #2 RATING: A rating assigned to wetlands in King County that are greater than one acre
in size; equal to or less than one acre in size and having a forested vegetation class; or the presence of heron
rookeries or raptor nesting trees.
III. SINGLE-WALLED: See RMC 4-5-120G.
JJJ. SITE: A single lot, or two (2) or more contiguous lots that, under common ownership or documented
legal control, were developed or are part of a development proposal.
KKK. SITE PLAN: A detailed plan drawing, prepared to scale, showing accurate boundaries of a site and the
location of all buildings, structures, uses, and principal site development features proposed for a speciflc
parcel or parcels of land.
LLL. SLOPE: An inclined ground surface the inclination of which is expressed as a ratio of horizontal
distance to vertical distance, which may be regulated or unregulated.
MMM. SLOPE, STEEP: A hillside, or portion thereof, which falls into one of two (2) classes of slope, sensitive
or protected.
1. Slope, Protected: A hillside, or portion thereof, with an average slope, as identifled in the City of Renton
Steep Slope Atlas or in a method approved by the City, of forty percent (40%) or greater grade and having a
minimum vertical rise of flfteen feet (15’).
2. Slope, Sensitive: A hillside, or portion thereof, characterized by: (a) an average slope, as identifled in the
City of Renton Steep Slope Atlas or in a method approved by the City, of twenty flve percent (25%) to less than
forty percent (40%); or (b) an average slope, as identifled in the City of Renton Steep Slope Atlas or in a
method approved by the City, of forty percent (40%) or greater with a vertical rise of less than flfteen feet (15’),
abutting an average slope, as identifled in the City of Renton Steep Slope Atlas or in a method approved by
the City, of twenty flve percent (25%) to forty percent (40%). This deflnition excludes engineered retaining
walls.
NNN. SMOKING LOUNGE: A club or facility where smoking occurs, including but not limited to the smoking
of any kind of lighted pipe, cigar, cigarette, or any other lighted smoking equipment.
OOO. SMP: City of Renton’s Shoreline Master Program.
PPP. SOCIAL SERVICE ORGANIZATIONS: Public or nonproflt agencies that provide counseling, therapy, job
training, educational classes, food banks, clothing banks, or other social or human services to persons
needing such services, but do not provide crisis intervention, day or night shelter, or case management. This
does not include religious institutions, offices, government facilities, schools, hospitals, clinics, day care,
homeless services uses, medical institutions, diversion facilities, lodging in any form, or residential uses.
QQQ. SOIL ENGINEER: A licensed civil engineer experienced and knowledgeable in the practice of soil
engineering.
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RRR. SOIL ENGINEERING: The application of the principles of soil mechanics in the investigation,
evaluation and design of civil works involving the use of earth or other materials and the inspection and
testing of the construction thereof.
SSS. SOIL ENGINEERING REPORT: A report including data regarding the nature, distribution, and strength
of existing soils, conclusions and recommendations for grading procedures and design criteria for corrective
measures when necessary, and options and recommendations covering adequacy of sites to be developed
by the proposed grading.
TTT. SOLAR ACCESS: Sunlight exposure on land without impairment by other development.
UUU. SOLAR ENERGY SYSTEM: A device or structural design feature, a substantial purpose of which is to
provide for interior lighting or provide for the collection, storage, and distribution of solar energy for space
heating or cooling, electricity generation, or water heating.
VVV. SOLAR ENERGY SYSTEM, GROUND MOUNTED, SMALL-SCALE: A solar energy system that is
structurally mounted to the ground and typically a size that would service a house, small business, or small
municipal building.
WWW. SOLID WASTE: Shall be deflned pursuant to WAC 173-350-100.
XXX. SPECIFIED ANATOMICAL AREAS:
1. Less than completely and opaquely covered human genitals, anus, pubic region, buttock, or female
breast below a point immediately above the top of the areola; or
2. Human male genitals in a discernibly turgid state, even if completely and opaquely covered.
YYY. SPECIFIED SEXUAL ACTIVITIES:
1. Human genitals in a state of sexual stimulation or arousal;
2. Acts of human masturbation, sexual intercourse, sodomy, oral copulation, or bestiality;
3. Fondling or other erotic touching of human genitals, pubic region, buttocks, or female breasts, whether
clothed or unclothed, of oneself or of one person by another; or
4. Excretory functions as part of or in connection with any of the activities set forth in this deflnition.
ZZZ. SPORTS ARENAS, AUDITORIUMS, AND EXHIBITION HALLS, INDOOR: A large enclosed facility used for
professional, semi-professional spectator sports, arena concerts, expositions, and other large-scale public
gatherings. This deflnition includes stadiums, concert halls, auditoriums, exhibition halls, and accessory
eating and drinking establishments. This deflnition excludes sports arenas or stadiums associated with
schools, cultural facilities, movie theaters, and entertainment clubs.
AAAA. SPORTS ARENAS, OUTDOOR: A large outdoor facility used for professional, semi-professional
spectator sports, arena concerts, and other large-scale public gatherings. This deflnition includes but is not
limited to stadiums, concert arenas, and accessory eating and drinking establishments. This deflnition
excludes sports arenas or stadiums associated with schools, cultural facilities, movie theaters, and
entertainment clubs.
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BBBB. STABLES, COMMERCIAL: A land use on which large lot domestic animals are kept for sale or hire to
the public. Breeding, boarding, or training of large lot domestic animals may also be conducted.
CCCC. STACKING SPACE: The space speciflcally designated as a waiting area for vehicles whose occupants
will be patronizing a drive-through business. Such space is considered to be located directly alongside a
drive-in window, facility or entrance used by patrons and in lanes leading up to the business establishment.
DDDD. START OF CONSTRUCTION: Includes substantial improvement and means the date the building
permit was issued; provided, the actual start of construction, repair, reconstruction, placement or other
improvement was within one hundred eighty (180) days of the permit date. The “actual start” means either the
flrst placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the
installation of piles, the construction of columns, or any work beyond the stage of excavation; or the
placement of a manufactured home on a foundation. Permanent construction does not include land
preparation, such as clearing, grading and fllling; nor does it include the installation of streets and/or
walkways; nor does it include excavation for a basement, footings, piers, or foundation or the erection of
temporary forms; nor does it include the installation on the property of accessory buildings, such as garages
or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the
“actual start of construction” means the flrst alteration of any wall, ceiling, fioor, or other structural part of a
building, whether or not that alteration affects the external dimensions of the building.
EEEE. STORAGE, BULK:
1. The holding or stockpiling on land of material and/or products where such storage constitutes forty
percent (40%) of the developed site area and the storage area is at least one acre, and where at least three (3)
of the following criteria are met by the storage activity:
a. In a bulk form or in bulk containers;
b. Under protective cover to the essential exclusion of other uses of the same space due to special flxtures
or exposed to the elements;
c. In sufficient numbers, quantities or spatial allocation of the site to determine and rank such uses as the
principal use of the site;
d. The major function is the collection and/or distribution of the material and/or products rather than
processing; and
e. The presence of flxed bulk containers or visible stockpiles for a substantial period of a year.
2. Bulk storage facilities include, but are not limited to:
a. Automobile holding and transfer depots;
b. Brick or tile storage and manufacturing;
c. Concrete block and products storage and manufacturing;
d. Contractor equipment yards;
e. Equipment or machinery of the stationary type not in use, not mounted on necessary foundations or
connected as required when during use, not designated and used as portable, and not stored in a warehouse.
This includes operable motor vehicles or wheeled equipment used only periodically where storage durations
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exceed those provided for parking lots as deflned in RMC 4-4-080, Parking, Loading and Driveway
Regulations;
f. Foundries;
g. Fuel yards, wholesale;
h. Grain or feed sites, elevators, or the open storage of grain and feed;
i. Log, random cut and chipped wood by-products storage;
j. Lumber mills and wholesalers;
k. Sand and gravel yards including sizing, transfer and loading equipment when present;
l. Scrap or junk yards and wrecking yards;
m. Solid waste holding and disposal areas;
n. Tank farms including distribution and loading systems.
3. Bulk storage facilities exclude:
a. Land banks, greenbelts, watersheds or public water reservoirs;
b. Parking lots or structures for private licensed automobiles;
c. Ship yards;
d. Warehouses alone or in conjunction with manufacturing on the site and when not including any of the
uses listed above in subsection 2a through 2n of this deflnition;
e. Facilities for storage of petroleum or any of its by-products, for use incidental to the primary use of the
property (e.g., heating, boiler or vehicular fuel or lubricants);
f. Retail service stations;
g. Retail sales lots for new or used automobiles.
FFFF. STORAGE, HAZARDOUS MATERIAL, ON-SITE OR OFF-SITE, INCLUDING TREATMENT: A facility
engaged in storage of materials, produced on-site or brought from another site, that are infiammable,
explosive, or that present hazards to the public health, safety, and welfare including all substances and
materials as deflned under hazardous materials, hazardous substances, and hazardous waste.
GGGG. STORAGE, OUTDOOR: The outdoor accumulation of material or equipment for the purpose of sale,
rental, use on site, or shipping to other locations. This deflnition excludes bulk storage, hazardous material
storage, warehousing and distribution, vehicle storage, and outdoor retail sales.
HHHH. STORAGE, SELF-SERVICE: A building or group of buildings consisting of individual, self-contained
units leased to individuals, organizations, or businesses for self-service storage of personal property. This
deflnition excludes indoor storage, warehousing, outdoor storage, bulk storage, and hazardous material
storage.
IIII. STORAGE, VEHICLE: An indoor or outdoor area for parking or holding of motor vehicles and boats or
wheeled equipment for more than seventy-two (72) hours. This deflnition excludes bulk storage, vehicle
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sales, vehicle rental, tow truck operation/auto impoundment yard, auto wrecking yard, outdoor storage, and
indoor storage.
JJJJ. STORM SEWER and STORM DRAIN: A sewer which carries storm surface water, subsurface water and
drainage. See RMC 4-6-100.
KKKK. STORMWATER FACILITY: A constructed component of a stormwater drainage system, designed or
constructed to perform a particular function, or multiple functions. Stormwater facilities include, but are not
limited to, pipes, swales, ditches, culverts, street gutters, detention ponds, retention ponds, constructed
wetlands, inflltration devices, catch basins, oil/water separators, and bioflltration swales. They may also
include low impact development BMPs/facilities. Also referred to as “Drainage Facility.”
LLLL. STORY: That portion of a building included between the upper surface of any fioor and the upper
surface of the fioor above, except that the topmost story shall be that portion of a building included between
the upper surface of the topmost fioor and the ceiling or roof above, unless such area meets the deflnition of
an attic. If the flnished fioor level directly above a usable or unused under-fioor space is more than six feet (6’)
above grade for more than flfty percent (50%) of the total perimeter or is more than twelve feet (12’) above
grade at any point, such usable or unused under-fioor space shall be considered as a story.
MMMM. STORY, FIRST: The lowest story in a building that qualifles as a story, as deflned herein, except that
a fioor level in a building having only one fioor level shall be classifled as a flrst story, provided such fioor level
is not more than four feet (4’) below grade for more than flfty percent (50%) of the total perimeter, or not more
than eight feet (8’) below grade at any point.
NNNN. STREAM ALTERATION: The relocation or change in the fiow of surface water runoff fiowing in a
natural or modifled channel.
OOOO. STREAM/LAKE CLASS: The stream and lake waters in the City are deflned by class as indicated in
RMC 4-3-050.
PPPP. STREET AMENITIES: See STREET FURNITURE.
QQQQ. STREET, ARTERIAL: Street intended for higher traffic volume and speed and classifled as a principal
or minor arterial on the City of Renton Arterial Street Plan.
RRRR. STREET, COLLECTOR:
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1. A street providing access with higher traffic volumes than a typical residential, commercial, or industrial
access street. Collector streets are designated by the Public Works Department.
2. A street classifled as a collector street on the City of Renton Arterial Street Plan.
SSSS. STREET, COMMERCIAL ACCESS: A non-arterial street providing access to commercial land uses.
TTTT. STREET FRONTAGE: The portion of a lot or structure abutting a public or private right-of-way. Structures
adjacent yet not adjoining a right-of-way shall be considered abutting if located within twenty feet (20’).
UUUU. STREET FURNITURE: Objects, such as outdoor seating, kiosks, bus shelters, tree grates, trash
receptacles, and fountains that have the potential for enlivening and giving variety to streets, sidewalks,
plazas, and other outdoor spaces open to, and used by, the public.
VVVV. STREET GRID PATTERN, MODIFIED: A street system based upon a traditional grid pattern; however,
offset intersections, loop roads, as well as angled or curved road segments may also be utilized on a limited
basis. The block pattern is characterized by regular (i.e., rectangular or trapezoidal) blocks.
WWWW. STREET GRID PATTERN, TRADITIONAL: A system of platting, or of street design, that features
parallel and perpendicular streets and intersections of streets at right angles that form short blocks.
XXXX. STREET, INDUSTRIAL ACCESS: A non-arterial street providing access to industrial land uses.
YYYY. STREET, PEDESTRIAN-ORIENTED: An area with streets and sidewalks speciflcally designated as such
and intended for use by people walking; with special design and spatial treatment of building frontages; built
at human scale; with uses of interest to and functional for people on foot; and designed to hold interest for
pedestrians by encouraging walking, browsing, and taking in the scene, as designated via Master Plans or
similar documents approved by the City.
ZZZZ. STREET, RESIDENTIAL ACCESS: A non-arterial street providing access to residential land uses, and
not designated as a collector street by the Public Works Department.
AAAAA. STREET WALL: A street wall is a building wall that generally abuts the sidewalk although there may
be occasional setbacks and recesses for the purpose of plazas and open space. The street wall helps deflne
and enclose the street corridor, creating a sense of activity, intensity, and spatial containment. Street walls
can incorporate arcades at the sidewalk level with habitable space above.
BBBBB. STRUCTURE: That which is built or constructed, an ediflce or building of any kind, or any piece of
work artiflcially built up or composed of parts joined together in some deflnite manner.
CCCCC. STRUCTURE: (This deflnition is for fiood hazard regulations in RMC 4-3-050 use only.) A walled
and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a
manufactured home.
DDDDD. STRUCTURE: (This deflnition for RMC 4-3-090, Shoreline Master Program Regulations, use only.) A
permanent or temporary ediflce or building, or any piece of work artiflcially built or composed of parts joined
together in some deflnite manner, whether installed on, above, or below the surface of the ground or water,
except for vessels.
EEEEE. SUBDIVISION: The division or redivision of land into lots, tracts, parcels, sites or divisions for the
purpose of sale, lease, or transfer of ownership. See also PLAT and PLAT, SHORT.
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FFFFF. SUBDIVISION: (This deflnition for RMC 4-3-090, Shoreline Master Program Regulations, use only.) A
parcel of land divided into two (2) or more parcels.
GGGGG. SUBDIVISION, PHASED: A subdivision which is, or is intended to be, recorded in increments over
a period of time.
HHHHH. SUBDIVISION, UNIT LOT: A division of land (parent site), for the purpose of sale, lease, or transfer
of ownership, underlying existing or proposed attached townhouse dwelling units that creates a unit lot for
each dwelling, for which one or more boundaries of the individual unit lots coincide with the walls of the
townhouse structure which separate individual attached townhouse dwelling units.
IIIII. SUBJECT PROPERTY: The tract of land which is the subject of the permit and/or approval action.
JJJJJ. SUBSTANTIAL DAMAGE: Damage of any origin sustained by a structure whereby the cost of restoring
the structure to its before damaged condition would equal or exceed flfty percent (50%) of the market value of
the structure before the damage occurred.
KKKKK. SUBSTANTIAL DEVELOPMENT: Any development of which the total cost or fair market value
exceeds flve thousand dollars ($5,000.00) or any development which materially interferes with the normal
public use of the water or shoreline of the State. Exemptions in RCW 90.58.030(3)(e) and in RMC 4-9-190.C
are not considered substantial developments.
LLLLL. SUBSTANTIAL DEVELOPMENT PERMIT: The shoreline management substantial development permit
provided for in Section 14 of the Shoreline Management Act of 1971 (RCW 90.58.140).
MMMMM. SUBSTANTIAL EXISTING IMPROVEMENTS: Physical improvements, such as residential and/or
commercial structures and their accessory structures, that have a reasonable remaining economic life as
indicated by their assessed valuation.
NNNNN. SUBSTANTIAL IMPROVEMENT: Any reconstruction, rehabilitation, addition or other improvement
of a structure, the cost of which equals or exceeds flfty percent (50%) of the market value of the structure
before the “start of construction” of the improvement. This term includes structures which have incurred
“substantial damage,” regardless of the actual repair work performed. The term does not, however, include
either:
1. Any project for improvement of a structure to correct previously identifled existing violations of state or
local health, sanitary, or safety code speciflcations that have been identifled by the local code enforcement
official and that are the minimum necessary to assure safe living conditions; or
2. Any alteration of a “historic structure”; provided, that the alteration will not preclude the structure’s
continued designation as a “historic structure.”
OOOOO. SUBTENANT: A person in possession of rental unit through the tenant with the knowledge and
consent, express or implied, of the owner.
PPPPP. SURFACE WATER DESIGN MANUAL: A manual, as it exists or may be amended, adopted by
reference by the City of Renton, which provides stormwater permit implementation and management
guidance consistent with the current version of the King County Surface Water Design Manual.
QQQQQ. SURVEY STANDARDS: City of Renton Survey Standards as adopted by the Planning/Building/
Public Works Department.
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(Ord. 2820, 1-14-1974; Ord. 3366, 10-15-1979; Ord. 3719, 4-11-1980; Ord. 4071, 6-1-1987; Ord. 4172, 9-12-
1988; Ord. 4346, 3-9-1992; Ord. 4367, 9-14-1992; Ord. 4517, 5-8-1995; Ord. 4521, 6-5-1995; Ord. 4522, 6-5-
1995; Ord. 4577, 1-22-1996; Ord. 4636, 9-23-1996; Ord. 4691, 1-6-1997; Ord. 4716, 4-13-1998; Ord. 4720, 5-4-
1998; Ord. 4724, 5-11-1998; Ord. 4828, 1-24-2000; Ord. 4832, 3-6-2000; Ord. 4835, 3-27-2000; Ord. 4848, 6-
26-2000; Ord. 4851, 8-7-2000; Ord. 4917, 9-17-2001; Amd. Ord. 4963, 5-13-2002; Ord. 5062, 1-26-2004; Ord.
5100, 11-1-2004; Ord. 5124, 2-7-2005; Ord. 5137, 4-25-2005; Ord. 5355, 2-25-2008; Ord. 5356, 2-25-2008;
Ord. 5450, 3-2-2009; Ord. 5496, 10-5-2009; Ord. 5526, 2-1-2010; Ord. 5578, 11-15-2010; Ord. 5633, 10-24-
2011; Ord. 5639, 12-12-2011; Ord. 5676, 12-3-2012; Ord. 5727, 10-20-2014; Ord. 5757, 6-1-2015; Ord. 5759,
6-22-2015; Ord. 5818, 10-17-2016; Ord. 5828, 12-12-2016; Ord. 5839, 6-12-2017; Ord. 5841, 6-12-2017; Ord.
5868, 12-11-2017; Ord. 5899, 11-19-2018; Ord. 5910, 12-10-2018; Ord. 5953, 11-18-2019; Ord. 5954, 11-18-
2019; Ord. 5963, 3-2-2020; Ord. 5976, 8-3-2020; Ord. 5977, 8-10-2020; Ord. 5996, 12-14-2020; Ord. 5999, 12-
14-2020; Ord. 6019, 6-14-2021; Ord. 6026, 9-20-2021; Ord. 6068, 6-13-2022; Ord. 6070, 6-13-2022; Ord.
6095, 11-28-2022; Ord. 6100, 12-5-2022; Ord. 6151, 11-25-2024)