Middle Housing in Washington

This page shares definitions, guidelines and technical support materials for local governments in Washington with an interest in pursuing middle housing as a part of their comprehensive planning and local regulations. 

Graphic depiction of small houses to duplex houses all the way up to high rise apartments
Graphic depicting middle housing types that could be included in single-family neighborhoods.

Middle Housing Overview

Middle housing is a term for homes that are at a middle scale between detached single-family houses and large multifamily complexes. Examples include: duplexes, triplexes, fourplexes, fiveplexes, sixplexes, courtyard apartments, cottage clusters, and townhomes. These types are typically “house-scale”; that is, the buildings are about the same size and height as detached houses. During the 2023-24 legislative session, HB 1110 (2023) was adopted to implement middle housing across the state.

HB 1110 (2023) Middle Housing Model Ordinances

HB 1110 (2023) directs Commerce to provide technical assistance including model ordinances, for implementing the bill.

MAKERS Architecture and Urban Design has been selected to lead a team to develop middle housing model ordinances with the Department of Commerce, supported by Neighborhood Workshop, ECONorthwest and Ogden Murphy Wallace. The model ordinances will be shaped by stakeholder engagement along with the team’s expertise in middle housing policy, land use planning, development regulations and economic analysis. The final model ordinances and user guide will support the work of cities across the state to implement HB 1110.

Model Ordinance Development Schedule

House Bill 1110 requires Commerce to publish model ordinances by January 23, 2024. 

The illustration below summarizes the process and timeline for preparing and publishing the model ordinances. Final products will include: a concept memorandum summarizing key issues to be addressed in the model ordinances. A public review draft of the model ordinances is scheduled for release in early November 2023, with the final model ordinances and a user guide to be published in January 2024.

Outreach Schedule

Schedule details and materials

The time frame to publish the final model ordinances is brief; however, community engagement will be part of the process. Forms of community engagement will include:

  • Technical Committee – A committee comprised of local government staff will review preliminary model ordinance drafts.
  • Stakeholder Outreach – Outreach to various stakeholder groups and organizations will take place from September 2023 to October 2023.
  • A 30-day public comment period on a public review draft of the model ordinances will occur, anticipated to begin in early November 2023.
  • A webinar on the model ordinance public review drafts and subsequent feedback is currently scheduled to be held November 9, 2023, during the 30-day public comment period.

In addition to the above, Commerce will hold several online drop-in open houses where the public may visit, ask questions and offer comments on HB 1110. Commerce staff will be available during these online drop-in dates and times. Open Houses will be held as follows:

If you would like to receive more information on the Model Ordinance process, please sign up for our mailing list using this online form.

Middle Housing Grants


The 2023-2025 State Operating Budget (Senate Bill 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 will make approximately $4.5 million available in statewide grants to implement House Bill 1110 (2023) supporting the development of middle housing. The grant window is currently open and will close on Friday, September 15, 2023 at 5 PM. Completed applications must be submitted to gmsgrants@commerce.wa.gov

Commerce hosted a pre-application workshop on August 17, 2023. Please see the following materials and video recording of the workshop.

Grant Requirements

Grants are available to local governments across the state that are subject to the requirements of HB 1110 during their next periodic review update cycle (2024-2027). Local governments not subject to HB 1110 may also apply for activities related to implementing middle housing. However, priority for grant funding will go to those local governments required to implement HB 1110. Funding will also be prioritized to local governments that did not receive funding under the Middle Housing grant program provided during the 2021-2023 biennium. 

Application Materials

Accessory Dwelling Units (ADU)

While ADUs are not defined as middle housing, they provide infill housing that fits into residential neighborhoods. HB 1337 (2023) requires all local governments planning under the GMA to allow two ADUs per lot within urban growth areas. Commerce will update ADU guidance and information on this page in addition to the resources below.

Middle Housing and ADU Resources

Middle Housing Tools

Before the adoption of HB 1110 (2023), Commerce developed information and tools to help local governments with an interest in middle housing. Please contact us if you need any of the following in an editable format.