As housing pressures continue to mount in Washington's growing population centers, a new law aims to quickly and cost-effectively increase the supply of accessory dwelling units, or ADUs. Governor Bob Ferguson has signed Substitute House Bill 1353, championed by Rep. Alex Ramel from Bellingham, into law, introducing a self-certification program for architects designing these units.
The program is designed to primarily streamline the process for detached ADUs, allowing architects who are registered to self-certify that their ADU plans are up to code. The intention is to desperately try to reduce the backlog on permitting, ease the burden on local planning departments, and ultimately make it cheaper to get these small homes built. Rep. Ramel pointed out in the House Democrats' news release, “This idea is already working in other states to cut permitting times and bring down costs.” He added, “It empowers architects to take responsibility for compliance while preserving safeguards through audits and inspections.”
Localities governed by the Growth Management Act (GMA) can opt into this program, but it's not mandatory. For those who do, the law requires them to audit at least 20% of all self-certified ADU applications each year, ensuring that despite the expedited process, oversight remains a priority. This balance between efficiency and compliance checks is at the heart of the bill's philosophy.
The law comes into effect 90 days after the legislative session ends, and it only applies to detached ADUs. Cities that choose to participate hope to quickly see a rise in ADU constructions, offering homeowners an opportunity to contribute to the housing supply.
