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 showing housing ranging from single family up to apartment complexes in size and occupancy
Photo courtesy of Opticos Design

What is "middle-housing"?

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.

How much housing and where will it go?

Statewide, about one million more homes are needed in the next 20 years, by 2044. (Draft HAPT – Calculator (Excel)) This is based on an analysis of housing needs by the Department of Commerce and population forecasts from the state Office of Financial Management. Most of the new housing will be in existing or planned urban areas that already have sewer, water, schools, and other infrastructure. Some of the homes will be stand-alone houses on individual lots, but many others will need to be different types that are more affordable and environmentally sustainable.

Why "middle-housing"?

Middle housing is one part of the way, under the Growth Management Act, to accommodate the local portion of countywide projected housing needs for households of all incomes. Middle housing benefits can include:

  1. Is less expensive per unit than a detached house.
  2. Fits well in residential neighborhoods and can mix with detached houses (a common practice in historic communities).
  3. Is suitable for today’s smaller families and single individuals.
  4. Is more affordable to a variety of households, including those with moderate incomes.
  5. Complements transit and walkability.
  6. Generally, has less environmental impacts per unit than a stand-alone house.
  7. Provides more opportunities for home ownership.
  8. Can create additional housing in urban areas without reducing land for farms, forests, and rural uses.


Commerce support

Housing survey

In a recent housing survey, the majority of respondents were in favor of several types of middle housing, such as triplexes, in single family zones. The survey, produced in partnership with the Puget Sound Regional Council and Commerce, randomly sampled Washingtonians about issues of statewide significance. You can read the full survey report here (PDF), or you can click on a link to the housing survey dashboard below.

Housing grants

Created for the 2022-2023 fiscal year, a middle housing grant program is currently available for cities with a 2024 comprehensive plan due date. This funding is being considered for continuation in the next fiscal year.

Middle housing tools

Commerce has hired Opticos Design to develop information and tools to help local governments with an interest in middle housing. Tools and support materials will be added to this webpage as they are completed.