Bill > SB5413

This bill establishes detailed regulations for detached accessory dwelling units (ADUs) outside urban growth areas in Washington state. Counties may allow these secondary housing units on a single parcel, but must enforce strict limitations: only one accessory dwelling unit is permitted per parcel, the unit cannot exceed 1,296 square feet, must be located within 150 feet of the primary dwelling, and use the same driveway. The bill requires documentation of adequate water and septic system capacity, mandates water withdrawals be metered, and ensures the units comply with existing water use restrictions. Counties must implement a code enforcement process that includes a voluntary compliance mechanism with escalating penalties for unpermitted units, including potential fines up to $1,000 and a three-year prohibition on obtaining ADU permits for repeat violations. Additionally, counties must track and report ADU permits annually and update their comprehensive land use plans to account for these new housing units, ensuring that the development of detached ADUs is carefully monitored and integrated into regional planning strategies. The legislation aims to provide flexibility for additional housing in rural areas while maintaining environmental and regulatory safeguards.

Housing and Urban Affairs

https://app.leg.wa.gov/billsummary?BillNumber=5413&Year=2025&Initiative=false