The bill establishes regulations for detached accessory dwelling units (ADUs) outside urban growth areas in Washington State. It allows counties to permit these units under specific conditions, including limitations on the number of units per parcel, compliance with water supply and sewage system requirements, and restrictions on size and location relative to the principal dwelling. The gross floor area of the ADU cannot exceed 1,296 square feet, and it must share a driveway with the primary unit. Additionally, if the ADU is used as a short-term rental, the primary unit must be owner-occupied, and water withdrawals must be metered.

Counties are required to track and report the number of ADU permits and their usage as short-term rentals annually. They must also update their comprehensive land use plans to reflect the number of ADUs and projected developments every five years. The bill amends existing definitions related to accessory dwelling units and clarifies that these new regulations do not affect previously adopted county ordinances or exclude other methods of authorizing ADUs.

Statutes affected:
Original Bill: 36.70A.696
Substitute Bill: 36.70A.696
Second substitute: 36.70A.696