Legislation to Lift Local Prohibition of Middle Housing Proposed in Washington State

Washington State is the latest example of a state that wants to preempt local planning law to make it easier to add housing units to single-family residential properties all over the states.

1 minute read

January 23, 2020, 9:00 AM PST

By James Brasuell @CasualBrasuell


Missing Middle Housing

A SE Portland duplex. | Sightline Institute: Missing Middle Homes Photo Library / Flickr

Dan Bertolet reports on statewide legislation introduced yesterday in Washington by State Representative Nicole Macri (D-Seattle) that would "lift local bans on small-scale, multiple-dwelling homes known as 'middle housing,'"

As explained by Bertolet, HB 2780 would re-legalize, "triplexes on any lot, and up to sixplexes in single-detached house zones in counties and cities of 15,000 or more," as well as, "duplexes on any lot in all cities between 10,000 and 15,000."

HB 2780 joins a growing roster of bills currently under consideration in the Washington Legislature that would ease zoning restrictions and other forms of housing regulation around the state. HB 2570 would ease the construction of backyard cottages and mother-in-law apartments. HB 1923, approved in 2019, increased building capacity around the state, but through incentives rather than a mandate.

HB2780 also joins a growing roster of bills in other states that would preempt local law to allow for more density in single-family zones around the state. Oregon already passed a law, but California, Maryland, Virginia, and Nebraska are considering similar reforms of the traditional single-family zoning designation to allow more space for homes of different sizes in residential neighborhoods.

Tuesday, January 21, 2020 in Sightline Institute

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

June 11, 2025 - Diana Ionescu

Rendering of Shirley Chisholm Village four-story housing development with person biking in front.

San Francisco's School District Spent $105M To Build Affordable Housing for Teachers — And That's Just the Beginning

SFUSD joins a growing list of school districts using their land holdings to address housing affordability challenges faced by their own employees.

June 8, 2025 - Fast Company

Yellow single-seat Japanese electric vehicle drivign down road.

The Tiny, Adorable $7,000 Car Turning Japan Onto EVs

The single seat Mibot charges from a regular plug as quickly as an iPad, and is about half the price of an average EV.

June 6, 2025 - PC Magazine

Rendering of autonomous cargo train moving across bridge across river in wooded area between Texas and Mexico.

Trump Approves Futuristic Automated Texas-Mexico Cargo Corridor

The project could remove tens of thousands of commercial trucks from roadways.

5 hours ago - FreightWaves

Rendering of white three-story single-stair building in Austin, Texas with staircase in the middle.

Austin's First Single Stair Apartment Building is Officially Underway

Eliminating the requirement for two staircases in multi-story residential buildings lets developers use smaller lots and more flexible designs to create denser housing.

6 hours ago - Building Design & Construction

MARTA bus with Atlanta skyline in background

Atlanta Bus System Redesign Will Nearly Triple Access

MARTA's Next Gen Bus Network will retool over 100 bus routes, expand frequent service.

7 hours ago - Mass Transit