Planning for Middle Housing

Commerce is directed to provide technical assistance, including publishing model ordinances, to implement the middle housing legislation. 

The model ordinances below include both Chapter 332, Laws of 2023 requirements, and optional development standards to facilitate middle housing development. Local jurisdictions may adjust optional standards not specified in Chapter 332, Laws of 2023 based on local preferences. To account for differing middle housing requirements based on a city’s population, one model ordinance has been prepared to assist cities 25,000 in population and greater, and the second ordinance for those cities less than 25,000 in population.

A user guide accompanies the middle housing model ordinances that provides background on the content of the model ordinances, link to resources and other guidance related to Chapter 332, Laws of 2023 implementation.

Model Ordinances and User Guide (originally published January 2024)

• Final Model Ordinance for cities 25,000 and over (PDF)
• Final Model Ordinance for cities under 25,000 (PDF)
• User Guide for Middle Housing Model Ordinances (PDF)

Updated Draft Middle Housing Model Ordinances

In March 2024, the Legislature passed HB 2321 (2024), amending part of Chapter 332, Laws of 2023. Commerce has prepared draft updates to the middle housing model ordinances and user guide to reflect these changes and also respond to issues raised since their original publication in January 2024. 

Updated Draft Model Ordinances and User Guide (published July 2024)

• Draft Model Ordinance for cities 25,000 and over (PDF)
• Draft Model Ordinance for cities under 25,000 (PDF)
• Draft User Guide for Middle Housing Model Ordinances (PDF)

The middle housing legislation (Chapter 332, Laws of 2023) offers two alternative pathways to comply with its statutory requirements. Each alternative has provisions that either require or may require Commerce certification or approval. Commerce has prepared interim guidance in the form of Fact Sheets for cities that may wish to use these alternatives.  

These following draft Fact Sheets describe an interim certification/approval and review process, application materials and approval/certification criteria.

• Requesting a timeline extension for middle housing implementation:
  • In areas at risk of displacement
  • In areas lacking capital facilities
• Request for approval of actions for substantially similar to middle housing

The guidance in the Fact Sheets is interim, until such time the Washington Administrative Code (WAC) update addressing housing bills is adopted in late 2024/early 2025. The adopted WAC will identify the final alternative pathway review and application processes.

Chapter 332, Laws of 2023 (Middle Housing) and Chapter 334, Laws of 2023 (Accessory Dwelling Units) set maximum off-street parking requirements that local governments may impose on middle housing and accessory dwelling units.

Both laws identify instances where the maximum off-street parking requirements would not apply. One of these instances is if a local government submits an “empirical parking study” to Commerce, which Commerce must then review and decide whether or not to certify.

Both laws require Commerce to develop guidance to assist cities and counties on items to include in the empirical parking study. Commerce has prepared empirical parking study guidelines for local governments to use in making a certification request to Commerce.

• Draft empirical parking study guidance (PDF)
• Draft empirical parking study application checklist (PDF) 

While ADUs are not defined as middle housing, they provide infill housing that fit into residential neighborhoods. Chapter 334, Laws of 2023 requires all local governments planning under the GMA to allow at least two ADUs per lot within urban growth areas, with some limitations. Final guidance and additional resources for local government planners are available.

ADU resources

• ADU Guidance (PDF)
• ADU Checklist (Word)
• Downloadable presentation for local use by cities (PPT)
• Viewable webinar on ADU’s for cities
• Downloadable presentation for local use by counties (PPT)
• Viewable webinar on ADU’s for counties
• More Accessory Dwelling Unit (ADU) Materials – EZView webpage

The 2023-2025 State Operating Budget, SB 5187, directs Commerce to administer grants and provide technical assistance to cities or counties for actions relating to adopting ordinances that plan for and accommodate housing. Commerce has made approximately $4.5 million available in statewide grants to implement Chapter 332, Laws of 2023 supporting the development of middle housing. 

Limited middle housing grant funds remain available to support middle housing implementation work. Refer to the grants page for more information.

• General Middle Housing FAQ (PDF)
• Jurisdictions subject to Chapter 332, Laws of 2023 (PDF)
• Middle Housing Building Types (PDF)
• Middle Housing Lot and Block Models (PDF)
• Middle Housing – Introduction (PPT)
• Middle Housing Study (PPT)
• Middle Housing – What, How and Where? (PPT)
• Middle Housing – How Do We Get More? (PPT)
• Middle Housing Summary of Resources (PPT)
• Middle Housing Presentation Videos

• Middle Housing Pro forma: Puget Sound Region Final (Excel)
• Middle Housing Pro Forma: Feasibility Attainability Slides (PDF)
• Middle Housing Pro Forma: Presentation Recording
• Appendix A: Middle Housing Market Assessment (PDF)
• Appendix B: Pro Forma Calibration and Assumptions (PDF)
• Appendix C: Middle Housing Pro Forma User Guide (PDF)
• Appendix D: Middle Housing Sensitivity Testing (PDF)

• Middle Housing Placetype Atlas (PDF)
• Middle Housing User Guide (PDF)
• Middle Housing Objective Design  Standard Basic Toolkit (PDF)
• Middle Housing Objective Design Standard Detailed Toolkit (PDF)