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WashingtonHB 13452025-2026 Regular SessionHouseWALLET

Establishing limitations on detached accessory dwelling units outside of urban growth areas.

Sponsored By: Sam Low (Republican)

Signed by Governor

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Bill Overview

Analyzed Economic Effects

3 provisions identified: 0 benefits, 2 costs, 1 mixed.

Owners face penalties for unpermitted backyard homes

Beginning June 11, 2026, counties allowing detached accessory homes outside urban growth areas must offer a voluntary compliance process. Owners using that process pay a permit penalty of at least twice the normal permit fee. Owners who skip it and receive an infraction for missing permits face at least a $1,000 fine and must remove the home or bring it into compliance. If the home stays and meets existing development rules, the permit penalty is at least three times the normal fee. Owners who skip voluntary compliance and receive the infraction also face a permit ban for new accessory homes lasting at least three years.

Rural backyard homes allowed with strict limits

Beginning June 11, 2026, Washington counties planning under the Growth Management Act can allow detached accessory homes outside urban growth areas. Counties must adopt the required enforcement and planning measures. Each parcel can have only one detached accessory home. Its floor area cannot exceed the county's attached-home limit or 1,296 square feet, excluding garages, porches, and unfinished basements. It must be within 150 feet of the main home and share its driveway and entrance and exit. Each home must have metered water withdrawals, and combined domestic withdrawals on the parcel must stay within state limits. Projects must meet water-supply and groundwater-mitigation requirements, and applicants must document enough sewage or septic capacity. These homes are barred on nonconforming lots smaller than one acre; owners cannot split parcels to avoid the limits. An existing single-family home can become the accessory home if it meets these requirements and a new single-family main home is built on the parcel. The law preserves earlier accessory-home ordinances and other ways to authorize these homes that are consistent with the new section.

Counties face caps on rural backyard housing

Beginning June 11, 2026, counties allowing these detached homes must track completed permits and report totals annually to Washington's Department of Commerce. At their next required plan review and later reviews, counties must count homes completed since that date. They must also account for projected development over 20 years and keep development outside urban growth areas within existing density limits. Plan changes for this purpose can occur no more than once every five years. Counties can allocate at most 10% of their rural population target to these homes in rural counties, or 7% in nonrural counties.

Sponsors & Cosponsors

Sponsor

  • Sam Low

    Republican • House

Cosponsors

  • Greg Nance

    Democratic • House

  • Mia Gregerson

    Democratic • House

  • Steve Tharinger

    Democratic • House

  • Strom Peterson

    Democratic • House

Roll Call Votes

All Roll Calls

Yes: 119 • No: 20

Senate vote • 3/3/2026

3rd Reading & Final Passage

Yes: 33 • No: 15 • Other: 1

House vote • 1/22/2026

3rd Reading & Final Passage

Yes: 86 • No: 5 • Other: 7

Actions Timeline

  1. Effective date 6/11/2026.

    3/27/2026House

  2. Chapter 231, 2026 Laws.

    3/27/2026House

  3. Governor signed.

    3/27/2026legislature

  4. Delivered to Governor.

    3/6/2026legislature

  5. President signed.

    3/4/2026legislature

  6. Speaker signed.

    3/4/2026legislature

  7. Third reading, passed; yeas, 33; nays, 15; absent, 0; excused, 1.

    3/3/2026House

  8. Rules suspended. Placed on Third Reading.

    3/3/2026House

  9. Placed on second reading by Rules Committee.

    2/24/2026House

  10. Passed to Rules Committee for second reading.

    2/19/2026House

  11. HSG - Majority; do pass.

    2/18/2026House

  12. First reading, referred to Housing.

    1/26/2026House

  13. Third reading, passed; yeas, 86; nays, 5; absent, 0; excused, 7.

    1/22/2026House

  14. Rules suspended. Placed on Third Reading.

    1/22/2026House

  15. Floor amendment(s) adopted.

    1/22/2026House

  16. Rules Committee relieved of further consideration. Placed on second reading.

    1/19/2026House

  17. By resolution, reintroduced and retained in present status.

    1/12/2026House

  18. Returned to Rules Committee for second reading.

    3/19/2025House

  19. Rules Committee relieved of further consideration. Placed on second reading.

    3/6/2025House

  20. Referred to Rules 2 Review.

    2/10/2025House

  21. HOUS - Executive action taken by committee.

    2/6/2025House

  22. HOUS - Majority; do pass.

    2/6/2025House

  23. First reading, referred to Housing.

    1/16/2025House

Bill Text

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