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Home My WebLink AboutPRADU LookbookPermit Ready ADU Program City of Renton February 2022 An Accessory Dwelling Unit (ADU) is a small, self-contained dwelling located on the same lot as a single-family home. Independent from the primary residence, ADUs provide the same basic func�ons – complete with a kitchen, living/sleeping area, and bathroom, but are designed to be smaller or “acces- sory.” The defini�on of an ADU may vary depending on the regula�ons adopted by the local jurisdic�on; Renton Municipal Code defines an ADU as “An inde- pendent subordinate dwelling unit that is located on the same lot, but not within a single family dwelling.” In other words, the City only allows free-standing ADUs. If the term ‘ADU’ is unfamiliar, you may be familiar with one of their alternate names: co�age house, granny flat, mother-in-law unit, carriage house, in-law suite, guest house, granny shack – and the list keeps growing! Historically, ADUs have played an important role in providing addi�onal housing where housing demand has exceeded the supply, especially in high cost communi�es. As a city located in King County, Renton is required to comply with the provisions of the Growth Management Act (GMA), which includes development and adop�on of a twenty-year comprehensive plan to help manage local growth. Comprehensive plans must include a sec�on for each of the GMA’s thirteen planning elements, which range from urban growth and economic development to sprawl reduc�on and housing. One of the tenets for the GMA’s housing element is to increase housing supply. State legisla�on requires jurisdic�ons to establish development regula�ons that now plans for the availability of affordable hous- ing to all economic segments of the popula�on, promote a variety of residen�al densi�es and housing types, and encourages preserva�on of exis�ng hous- ing stock (RCW 36.70A.020). To that end, local jurisdic- �ons are u�lizing ADUs to create affordable housing opportuni�es and increase and diversify housing inventory while maintaining the character of single-family neighborhoods. A-D-What? A-D-Who? • Builds on exis�ng public investment and infrastructure, reducing the need for new investment • Supports City’s efforts to meet household growth targets in accordance with the Growth Management Act • Increases housing stock for market-rate and affordable housing • Builds wealth, promotes housing stability • Increases property values • Creates independent housing op�on for diverse households and lifestyles • Allows older adults to “age-in-place” • Supports infill development in exis�ng neighborhoods while maintaining neighborhood quality and character Benets to ADU Development Incentivizing ADU Development In 2017 the City began brainstorming ways to incen�vize ADU develop- ment; the following informa�on summarizes a few of the changes that we have implemented and projects currently underway: » Renton City Council approved a 50% fee reduc�on for applicable ADU fees, including building, mechanical and electrical permits, impact fees for transporta�on, parks, and fire, and system development charges, otherwise known as u�lity hook-up fees (2017). » Staff streamlined the applica�on and building permit process, reducing turnaround �me by 4-6 weeks (2019). » Staff updated development regula�ons to create flexibility for parking, height, and size requirements and leniency for accessory building and garage conversions (2019, 2020). » Council approved an extension and amendment of the 2017 legisla�on that reduced the applicable ADU fees listed above, and furthering reducing them to 100%, with the excep�on of u�lity hook-up fees, which will con�nue to be charged at 50%, through December 31, 2024 (2020). » Renton School District has agreed to waive impact fees for proper�es served in their school district through December 31, 2024. In addi�on to reducing fees, upda�ng development regula�ons and streamlining our applica�on process, we developed eight fully designed, pre-engineered and pre-approved ADU base plans that now available to property owners in the City of Renton who are interested in building an ADU of their own. For a nominal permit recording fee and processing fee, eligible par�es will receive complete construc�on plans and a City-pro- duced site plan. These changes were implemented with the intent of providing property owners a significant cost savings of thousands of dollars that could be applied toward construc�on labor and building materials. We were very inten�onal in crea�ng a selec�on of ADUs that could be built on residen�al lots, both large and small. As a result, the available PRADU base plans offer a wide variety of op�ons. The maximum ADU size allowed on a given lot is determined by mul�ple factors, including the size of the lot and primary residence, and the maximum impervious surface coverage allowed in the zone where the property is located. To determine the maximum PRADU size that can be built on your lot, we’ll need to consider the following ques�ons: WHAT IS THE TOTAL AREA OF YOUR LOT (SQ. FT.)? If you don’t know your lot size, please consult the King County Parcel Viewer, Renton ‘COR’ Maps, or request assistance from the City of Renton’s Planning Custom- er Service. WHAT IS THE TOTAL AREA OF YOUR HOME? The total area of the ADU shall not exceed 75% of the total area of the primary residence. For example, if the primary dwelling is 1,000 sq. �., the ADU cannot be larger than 750 sq. �., and it must not exceed the size allowed on the lot where it is located. In other words, even if the primary dwelling is 1,000 sq. �., if the lot size ranges from 3,001 to 4,999 sq. �., the ADU would need to comply with the maximum lot size allowed. WHAT IS YOUR PROPERTY’S RESIDENTIAL ZONING DESIGNATION? You will need this informa�on to determine the maximum impervious surface area coverage allowed. If you do not know the residen�al zoning designa�on where your residence is located, consult Renton ‘COR’ maps or contact Planning Customer Service. If you do know your zoning designa�on, please see the table below: Selecting a PRADU If you don’t know the current impervious surface area coverage, you’ll need to calculate it. STEP 1. Put away your tape measurer! Visit the King County Parcel Viewer or Renton ‘COR’ maps to deter- mine the total area of your lot. STEP 2. Create an inventory of all of the impervious surfaces and associated area they individually compromise, such as the building footprint of your home, any accessory buildings, pa�os, driveways, sidewalks, etc. STEP 3. Get your calculator ready – you will need to add the total of all the impervious surface areas and divide it by the total area of your lot and mul�ply it by 100 to determine the percentage occupied by impervious surface. For example: (Total impervious surface area ÷ area of lot) x 100 = Impervious surface area % (2,500 ÷ 6,600) x 100 = 38% If you determine that you already exceed the impervious surface area in your residen�al zone, or if the addi�on of an ADU would exceed the impervious surface area allowed, onsite changes will need to be made to accommodate the ADU and comply with the City’s impervious surface standards. SELECTING A PRADU... Now that you have determined the total area of your lot, the size and zoning designa�on of your primary structure, and calculated your impervious surface coverage, you should have the informa�on you need to select a PRADU that complies with the City’s residen�al development regula�ons. As shown below, you always have the op�on to build a smaller dwelling than what is permi�ed by the lot size. What is the Current Impervious Surface Area Coverage on your Property? IF YOUR LOT IS... 3,000 sq. �. or less 3,001 - 4,999 sq. �. 5,000 - 6,999 sq. �. 7,000 - 8,999 sq. �. Greater than 9,000 sq. �. BASED ON LOT SIZE, THE ADU CANNOT EXCEED... 600 sq. �. 700 sq. �. 800 sq. �. 900 sq. �. 1,000 sq. �. OPTIONS AVAILABLE, BASED ON LOT SIZE... A, B, J A, B, C, G, J A, B, C, E, G, J A, B, C, E, G, J A, B, C, D, E, G, J, M ADAMS|1 BR / 1 BA A1 A2 A3 select your ADAMS - Model A •Living area: 520 sq. �. •Dimensions: 20 �. x 26 �. •Note: Dimensions may vary depending on model selected •Slab-on-grade plans available •Primary home must be larger than 694 sq. �. *Exact building area and dimensions may vary depending on model selected. ADAMS|1 BR / 1BA A4 A5 A6 ADAMS - Model A •Living area: 520 sq. �. •Dimensions: 20 �. x 26 �. •Slab-on-grade plans available •Primary home must be larger than 694 sq. �. *Exact building area and dimensions may vary depending on model selected. BAKER|1 BR / 1 BA B1 B2 B3 BAKER - Model B •Living area: 418 sq. �. •Dimensions: 16 �. x 26 �. •Primary home must be larger than 557 sq. �. Main Floor Loft Floor Plan *Exact building area and dimensions may vary depending on model selected. BEDROOM CASCADE|2 BR / 1 BA C1 C2 C3 C4 CASCADE - Model C •Living area: 650 sq. �. •Dimensions: 24 �. x 30 �. •Primary home must be larger than 867 sq. �. •Slab-on-grade plans available *Exact building area and dimensions may vary depending on model selected. GLACIER|3 BR / 2 BATH D1 D2 D3 GLACIER - Model D •Living area: 1,000 sq. �. •Dimensions: 25 �. x 26 �. •Primary home must be larger than 1,333 sq. �. First Floor STOVESTAIRS Second Floor *Exact building area and dimensions may vary depending on model selected. 11 ENCHANTMENT|2 BR / 2 BA E1 E2 E3 ENCHANTMENT - Model E •Living area: 750 sq. �. •Dimensions: 26 �. x 15 �. •Primary home must be larger than 1,000 sq. �. First Floor Second Floor STAIRS STAIRS *Exact building area and dimensions may vary depending on model selected. OLYMPICS|2 BR / 1 BA Main FloorGarage Floor G1 G2 G3 OLYMPICS - Model G •Living area: 602 sq. �. •Garage area: 602 sq. �. •Dimensions: 24 �. x 26 �. •Primary home must be larger than 803 sq. �. *Exact building area and dimensions may vary depending on model selected. HELENS|2 BR / 1 BA J1 J2 J3 HELENS - Model J •Living area: 624 sq. �. •Garage area: 512 sq. �. •Dimensions: 36 �. x 20 �. •Primary home must be larger than 832 sq. �. Garage Floor Main Floor *Exact building area and dimensions may vary depending on model selected. TOWNSEND|3 BR / 2 BA M1 M3 M2 TOWNSEND - Model M •Living area: 989 sq. �. •Dimensions: 36 �. x 30 �. •Primary home must be larger than 1,319 sq. �. *Exact building area and dimensions may vary depending on model selected. CITY OF RENTON | COMMUNITY & ECONOMIC DEVELOPMENT 1055 SOUTH GRADY WAY FLOOR 6 RENTON, WASHINGTON 98057 PLANNINGCUSTOMERSERVICE@RENTONWA.GOV 425.430.7200 | WWW.RENTONWA.GOV