Update · June 2026

HB 1110 status across Puget Sound

Where King County cities stand on adopting their middle-housing codes.

Washington's HB 1110 requires cities to legalize middle housing, but each city adopts its own implementing code on its own timeline — tied to its Growth Management Act comprehensive-plan update. For developers, that means what's buildable today varies by city. Here's a snapshot of where the Puget Sound region stands.

Tier 1 cities (four to six units)

As the region's largest city, Seattle adopted its updated Neighborhood Residential code and is among the furthest along, allowing four to six units on most residential lots. Bellevue, Kent, Renton, Auburn, Federal Way and other larger King County cities are Tier 1 jurisdictions with the same four-to-six-unit baseline, at varying stages of code adoption.

Tier 2 cities (two to four units)

Kirkland, Redmond, Sammamish, Mercer Island, Issaquah, Shoreline, Burien and Des Moines fall into Tier 2 or are transitioning, generally allowing two to four units depending on transit proximity and affordability.

What's next

As more cities finalize their codes through 2026 and 2027, Civexa is adding each one — with feasibility logic built from that city's actual adopted code. Check back here for city-by-city updates.