Image by Spicypepper999 - Own work, CC0

Under the leadership of Mayor Mark Mullet and the City Council, the City of Issaquah has taken an important step to streamline housing production by adopting Washington's first accessory dwelling unit (ADU) self-certification program. This action reflects the City's commitment to pursuing innovative solutions that reduce permitting barriers while maintaining accountability.

Approved by the Issaquah City Council on July 20, the new permitting pathway allows licensed architects to self-certify qualifying detached ADUs under 1,000 square feet to bypass duplicative building plan review, reducing unnecessary review steps while maintaining important safety and environmental protections.

MBAKS supported the ordinance throughout the process and submitted a letter of support outlining how the proposal can help reduce permitting delays, lower development costs, and encourage the construction of additional housing throughout the city.

A First-in-Washington Housing Reform

While several Washington jurisdictions have adopted pre-approved ADU plans, Issaquah is the first local city in the state to implement a self-certification program authorized under RCW 36.70A.683, legislation enacted by the Washington State Legislature in 2025.

The law allows certain jurisdictions to establish self-certification programs for ADUs, recognizing that licensed design professionals can play a greater role in certifying code compliance and reducing permitting bottlenecks.

By embracing this authority, Issaquah is positioning itself as a statewide leader in housing innovation and demonstrating a willingness to pursue practical solutions that can increase housing opportunities.

How the Program Works

Under the new ordinance, Washington-licensed architects may certify that a detached ADU complies with applicable building code requirements, eliminating the need for the City's traditional building code plan review for qualifying projects.

Importantly, the ordinance does not eliminate local oversight. The City will continue to conduct reviews related to land use compliance, stormwater management and more. This will ensure projects can benefit from a more efficient permitting process while maintaining the site-specific reviews necessary to protect public safety and environmental resources.

Why It Matters

Accessory dwelling units continue to be one of the most effective tools available for increasing housing supply within existing neighborhoods. ADUs can provide housing opportunities for family members, aging parents, caregivers, young professionals, and local workers while making efficient use of existing infrastructure.

However, lengthy permitting timelines, uncertainty, and regulatory costs frequently discourage homeowners from pursuing projects. By reducing duplicative review processes, Issaquah's new program is intended to remove barriers that often prevent housing from being built.

MBAKS Applauds Issaquah's Leadership

MBAKS commends Mayor Mark Mullet, the Issaquah City Council, Community Planning & Development staff, and the Issaquah Community for advancing this innovative policy.

As communities across Washington continue searching for ways to expand housing choices, Issaquah has established a model that other cities should consider. By implementing a practical, common-sense permitting reform authorized by state law, the City has demonstrated that it is possible to increase efficiency while maintaining accountability and public safety.