Bill > SB5470

This bill establishes limitations on detached accessory dwelling units (ADUs), which are separate housing units on the same property as a main home, when they are located outside of designated urban growth areas. Counties can permit these detached ADUs if they meet specific requirements, including having no more than one attached or detached ADU per parcel, adhering to water supply and sewage capacity regulations, and limiting the detached ADU's size to no more than 1,296 square feet, excluding garages and unfinished areas. The detached ADU must also share a driveway with the main home, be located within 150 feet of it, and cannot be built on forestland. If the detached ADU is used as a short-term rental, the primary home must be owner-occupied. Additionally, counties must track and report the number of detached ADUs permitted and used as short-term rentals, and update their comprehensive land use plans to account for these units within the overall density outside urban growth areas. The bill also amends existing definitions to include detached ADUs and references to this new section.

Budget and Finance, Housing and Urban Affairs

https://app.leg.wa.gov/billsummary?BillNumber=5470&Year=2025&Initiative=false