Planning commission backs code changes to allow new housing in existing buildings, tightens parking and envelope limits

The Mercer Island Planning Commission on April 23 voted to recommend amending city development regulations to comply with House Bill 1042 (RCW 35A.21.440), a 2023 state law that requires cities to allow addition of new dwelling units in existing commercial and mixed-use buildings in specified zones.

The change would add a new section to Mercer Island City Code chapter 19.06 to implement the state law for the city’s planned business (PBZ), commercial office (CO), business (B), MF-2 and town center zones. Staff said the code must be amended by June 30 to avoid state preemption. The commission’s recommendation will be packaged as a written report for the City Council; staff said the council’s first reading is scheduled for June 3 and a second reading and adoption for June 17.

The commission’s recommendation includes several specific amendments the commission debated and approved. Commissioners voted to: (1) require retention of existing parking quantity when dwelling units are added, replacing discretionary language that had allowed the code official to decide whether parking could be reduced; (2) allow modest site and exterior features tied to residential conversions, subject to limits; and (3) permit unenclosed…