WA HB1345

Counties planning under the Growth Management Act may allow detached accessory dwelling units (DADUs) outside urban growth areas, limited to one ADU per parcel with a maximum of 1,296 square feet, located within 150 feet of the principal unit and sharing its driveway

DADUs must comply with water supply requirements under RCW 19.27.097, with metered water withdrawals that cannot exceed domestic use limits, and applicants must demonstrate adequate sewage/septic capacity

Counties must establish code enforcement measures including voluntary compliance with double permit fees, a minimum $1,000 civil infraction for unpermitted construction with triple fees if brought into compliance, and a three-year permit ban for non-compliant owners

Counties must annually report DADU permits to the state, update comprehensive land use plans to account for completed and projected DADUs within overall rural density limits, and may only amend these provisions once every five years

Existing county ordinances authorizing ADUs remain valid, and the bill does not preclude other methods of authorizing ADUs consistent with its provisions