OLYMPIA – Governor Bob Ferguson has signed Substitute House Bill 1353 into law, a measure sponsored by Rep. Alex Ramel (D-Bellingham) aimed at accelerating the construction of accessory dwelling units (ADUs) across Washington.
The new law creates a voluntary self-certification program that allows registered architects to certify that detached ADU plans comply with building codes in cities governed by the Growth Management Act (GMA). The goal is to reduce permitting delays, cut costs, and ease the burden on local planning departments.
“This idea is already working in other states to cut permitting times and bring down costs,” said Rep. Ramel. “It empowers architects to take responsibility for compliance while preserving safeguards through audits and inspections.”
Cities may choose to participate in the program and are required to audit at least 20% of self-certified applications annually. The law applies only to detached ADUs and takes effect 90 days after the end of the legislative session.