Washington Growth Board Sets Statewide Precedent on GMA Affordable Housing Compliance

In a decision issued on August 1, 2025, for Futurewise v. Mercer Island, the Growth Management Hearings Board held that Mercer Island's comprehensive plan update failed to comply with key affordable housing provisions of Washington state's Growth Management Act (GMA), as amended by HB 1220 (2021). The Board found the City's housing element and land capacity analysis unlawful for failing to identify sufficient land and policy mechanisms to accommodate housing for extremely low, very low, and low-income households as required by RCW 36.70A.070(2)(c)–(d) and Goal 4 of the GMA.

The ruling is among the first to interpret and enforce the new standard imposed on all jurisdictions to "Plan for and accommodate housing affordable to all economic segments of the population of this state," introduced by HB 1220. The Board found that Mercer Island's comprehensive plan update aggregated the lower-income households into a single category for its land capacity analysis and assumed that incentive-based zoning and subsidies would address affordability for household incomes below moderate income. The Board rejected that assumption, holding that the City cannot rely on speculative subsidy programs to meet its housing targets, and must instead demonstrate a realistic plan for providing housing at each income level.

Following the decision, Mercer Island filed a petition for judicial review in King County Superior Court, challenging the Board's ruling. While the court case may take months to resolve, the decision has already prompted jurisdictions across Washington to reexamine their upcoming comprehensive plan updates and implementing regulations.

The DWT land use team is closely tracking this case and is available for questions.

Ken Nelson writes on land use issues in Washington state and beyond. Stay informed and subscribe to insights by Davis Wright Tremaine's land use practice.