Washington State Housing Legislative Updates

Middle housing refers to housing types that are similar in size, shape, and style to single-family houses.

Examples include multiplexes (e.g., duplex, triplex, fourplex, and sixplex), townhouses, stacked flats, courtyard apartments, and cottage houses.

To comply with the HB 1110 state mandates, the City of Renton must make the following updates to its zoning and development regulations:

• Allow middle housing units within all residential zones: A maximum of four housing units per lot allowed unless higher densities are permitted.

• Lots with affordable housing: A maximum of six housing units per lot allowed if at least two of the units are affordable housing unless higher densities allowed.

• Lots near a major transit stop: A maximum of six housing units per lot allowed when within a 1/4 mile walking distance of a "major transit stop" unless higher densities allowed. 

More Information: House Bill 1110 report, Your Voice Renton, and adopted legislation

An ADU refers to a dwelling unit located on the same lot as a single-family housing unit, duplex, triplex, townhome, or other housing unit. They provide the same essential functions as a typical residence, complete with a kitchen, bedroom(s), and bathroom(s).

To comply with the HB 1337 state mandates, the City of Renton must update its municipal code to comply with the following:

• General standards: Cannot impose setback requirements, yard coverage limits, tree retention mandates, restriction on entry door locations, aesthetic requirements, or requirements for design review for ADUs that is more restrictive than those for single-family residences.

• ADU quantity and type: Allow a minimum number of two ADUs per lot and must allow ADUs to be attached, detached or a combination of both.

• ADU size: Allow ADUs to be smaller than 1,000 sq ft.

• Owner occupancy: Does not require onsite owner occupancy.  

More Information: House Bill 1337 report, Your Voice Renton, and adopted legislation

HB 1110 and HB 1337 offer increased flexibility based on distance to a major transit stop. The Washington State Legislature established two distinct definitions of a major transit stop; see below for more information for a summary of each and how they apply to middle housing and ADUs.

HB 1110 – Middle Housing

In residential zones Resource Conservation (RC), Residential-1 (R-1), Residential-4 (R-4), Residential-6 (R-6), and Residential-8 (R-8) where middle housing is proposed, up to four dwelling units are allowed per lot. Additionally, up to six dwelling units are allowed per lot on all lots within one-quarter mile walking distance of a major transit stop.

HB 1110 defines a major transit stop as:

• A stop on high-capacity transportation system funded or expanded under the provisions of Chapter 81.104 RCW;
• Commuter rail stops;
• Stops on rail or fixed guideways systems; and
• Stops on bus rapid transit routes, including those under construction.

HB 1337 – ADUs

In residential zones Resource Conservation (RC), Residential-1 (R-1), Residential-4 (R-4), Residential-6 (R-6), Residential-8 (R-8), Residential-10 (R-10), and Residential-14 (R-14) where ADUs are proposed and within a one-half (1/2) mile walking distance of a major transit stop, ADU parking is not required.

HB 1337 defines a major transit stop as:

• A stop on high-capacity transportation system funded or expanded under the provisions of Chapter 81.104 RCW;
• Commuter rail stops;
• Stops on rail or fixed guideways systems, including transitways;
• Stops on bus rapid transit routes or routes that run on high-occupancy vehicle lanes; or
• Stops for a bus or other transit mode providing actual fixed route service at intervals of at least 15-minutes for at least five (5) hours during the peak hours of operations on weekdays.

To help the public understand and take advantage of these incentives, walkshed layers have been created in the city's online mapping software, COR Maps, to help support questions related to ADUs and middle housing. These layers can be found in COR Maps under the Land Use and Zoning group or by visiting the standalone ADU and Middle Housing Walkshed Map. For ease of implementation, all parcels within the walkshed / buffer area, whether fully or partially within the buffer, will be considered within the walkshed. 

After a year of discussion, planning, public engagement, and coordination with Renton's Planning Commission, the Planning and Development Committee directed staff to prepare an ordinance for Council approval. Following approval, staff will update the RMC Title 4 Development Regulations. The new development regulations are scheduled to take effect on June 30th, 2025.  

Staff presented proposed recommendations for new legislative state compliance to Planning Commission on the following dates:

Briefing: March 19, 2025
Public Hearing: April 2, 2025
Deliberations and Recommendation: April 16, 2025

Click here for all meeting agendas and Zoom recordings.

For property specific questions, email the Planning Division at: planningcustomerservice@rentonwa.gov. Please include the property address in the email subject and/or body of the email.