How is Snohomish County Implementing HB 1110 and 1337 before the 6/30/2025 deadline?...and Middle Housing Q and A

by Shauna Naf

Jun 07, 2025

JUNE 6, 2025

Issue 3

How is Snohomish County Implemeting HB 1110 and 1337?

Snohomish County updated their Comprehensive Plan in December of 2024 (you can review the full Comprehensive Plan and accompanying documents and maps here: https://www.snohomishcountywa.gov/5597/2024-Update). Cities in Snohomish County have until the end of June to implement the changes outlined in House Bill 1110 (middle housing) and House Bill 1337 (the ADU bill).

As a quick reminder, HB 1110 would apply to cities with a population over 25,000, allowing at least duplexes throughout, but HB 1337 allows for ADUs both within city limits as well as the urban growth area (which is generally in the county jurisdiction, not the city). There are also some cities that have fewer than 25,000 people but that are located in counties with a population of more than 275,000 and who also share an urban growth area with the largest city in the county to whom HB 1110 applies.

Snohomish County just updated their ADU FAQ for urban growth areas that are under their jurisdiction: https://snohomishcountywa.gov/DocumentCenter/View/8052/12---Accessory-Dwelling-Units-Detached-PDF

How are other Snohomish cities progressing in implementing HB 1110 and 1337? Read on!

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