In a landmark decision, Washington's Growth Management Hearings Board (GMHB) ruled that the city of Mercer Island failed to meet state requirements for affordable housing, forcing the city back to the drawing board. The ruling came after an appeal from the land use advocacy group Futurewise, which argued that Mercer Island’s 2024 growth plan fell short of the new standards set by House Bill 1220 (HB 1220). This legislation, a significant change to growth planning, requires cities to specifically plan for future housing needs across a broad range of income levels, not just a single, high-level growth target.

In 2023, Washington State enacted House Bill (HB) 1293, a pivotal piece of legislation that fundamentally reshapes how cities and counties can regulate building design under the Growth Management Act (GMA). This new law, codified as RCW 36.70A.630, introduces two critical requirements for local design review standards: they must be clear and objective, and they absolutely cannot reduce development intensity below the level generally permitted by a property's zoning. For the City of Mercer Island, this means a significant overhaul of its existing design standards, enshrined in Mercer Island City Code (MICC) Chapters 19.11, 19.12, and 19.15, which date back to 1972. The city has until June 30, 2025, to achieve full compliance.