This bill establishes a self-certification program for accessory dwelling unit (ADU) project permit applications in cities that plan under chapter 36.70A RCW. It allows registered architects to self-certify compliance with building code requirements for the construction of detached ADUs. The bill mandates that cities adopt specific rules for the self-certification program, including professional requirements for architects, random audits of self-certified applications, penalties for failed audits, and insurance coverage requirements. Additionally, cities must create a self-certification form that includes various attestations and agreements from the architect and property owner.

Furthermore, the bill requires cities operating a self-certification program to report on their activities by July 31, 2028, detailing the number of self-certified projects, permit issuance, and audit results. The Department of the state will maintain a database of architects subject to penalties due to failed audits, ensuring that no city accepts applications from those architects. Importantly, the bill clarifies that it does not affect the validity of any existing self-certification programs prior to its enactment.