Mercer Island planning commission recommends upzones, inclusionary housing and daylight-plane tweak; sends package to council

The Mercer Island Planning Commission voted 5–0 on June 10 to recommend that the City Council adopt a package of amendments to the comprehensive plan, a newly created station sub area plan and related development-code revisions intended to respond to a Growth Management Hearings Board remand.

Principal planner Adam Zach told commissioners the 2024 comprehensive-plan update was appealed to the Growth Management Hearings Board and that four issues were remanded to the city: land-capacity reanalysis disaggregated by affordability, adequate-provisions to support affordable housing, adoption of a station sub area plan, and anti-displacement measures. “The city has until July 31st of this year to complete its compliance with the board’s order,” Zach said, urging the commission to finish its recommendation so the council can complete the legislative steps.

Why it matters: The package (agenda bill PCB26-08) includes zoning changes aimed at adding housing capacity near the light-rail station, new affordability requirements, and code edits the city says are necessary to meet the board’s order. Staff and consultants told the commission these changes are intended to produce additional capacity at a range of income levels rather than simply increase the total unit count.

What the plan would do: The proposal would upzone the town center to allow buildings up to eight stories and incorporate some adjacent multifamily zones into the town center with a six-story maximum (TCMF6). The implementing code changes would add an inclusionary requirement that 10% of units in the town center and adjacent multifamily zones be affordable to households at 50% of area median income (AMI), with a fee-in-lieu option that would direct funds to projects providing deeper affordability. Staff also described code revisions to align permanent supportive, transitional and emergency housing rules with recent state law changes and to add consistency amendments across the development code.

Station-area approach and timing: The station sub area plan is divided into two phases. Phase 1 — the immediate zoning and code edits in the draft — would be adopted concurrently with the comprehensive plan. Phase 2 is a longer process, anticipated to begin after adoption and to include detailed design and compatibility work over a two-to three-year period, with some Phase 2 changes targeted for adoption by 2029.

Public reaction: During the continued public hearing, residents raised questions about notice, the number and location of affordable units, whether current buildings would be demolished and how supportive housing would be sited. Kevin Richards asked if the 10% requirement meant “10 units, 100 units, [or] a thousand units” and urged more outreach so “everyone on Mercer Island” can follow the process. Anita Mweeni raised state law HB 2266 and said recent changes remove the prior pre-approval hearing requirement for emergency or permanent supportive-housing projects; she asked whether proposed affordable housing would be rental or ownership.

Design dispute and amendment: Commissioners debated how the daylight-plane design standard should work with taller buildings. Staff had clarified that the daylight-plane measurement (the 30-foot horizontal depth) begins at the edge of the sidewalk adjacent to the building; commissioners debated whether to retain the standard’s existing lower start height or to move the start higher to accommodate eight-story buildings. The commission approved an amendment to section 19130 A6A clarifying that the stepback would start at 27 feet above the sidewalk and step back at a 45-degree angle up to a calculated height of 57 feet before the façade could continue vertically; that amendment passed 3–2.

Vote and next steps: After adopting the daylight-plane amendment, the commission voted 5–0 to forward the amended drafts to the city council as its recommendation. Staff told the public the commission’s recommendation will be presented to council on June 16; the ordinances are scheduled for first reading July 7 and second reading (possible adoption) July 21.

Authorities and related measures: Staff said anti-displacement measures will be addressed separately by ordinance 267 and that those measures fall under Title 5 of the city code and go directly to council. The Growth Management Hearings Board order — cited repeatedly in the hearing — drove the need to disaggregate capacity by affordability.

What remains unresolved: Staff and commissioners agreed Phase 2 will require more detailed design study and public engagement. The precise number of additional units and the number of affordable units that will result from the upzones were not recalculated based on the final daylight-plane amendment and remain “not specified” in the hearing record. The commission and staff noted that further public comment opportunities exist at council hearings.

Commissioners and officials quoted in this article spoke at the June 10 public hearing and during the planning-commission deliberations. The commission’s recommendation and the full record are scheduled to move to the City Council on June 16 for legislative review.