Mountlake Terrace planners weigh Middle Housing code changes, set expedited drafting schedule

Mountlake Terrace Planning Commission members on March 24 reviewed proposed development-code amendments aimed at implementing Washington state's HB 1110 middle-housing requirements and gave staff direction to prepare a draft for submittal to the state Department of Commerce.

The discussion, led by consultants and city planning staff, covered lot-area minimums, how many units can be allowed per lot in low-density zones, whether to use lot-coverage or floor-area-ratio (FAR) to scale buildings, height and rear-yard limits for accessory dwelling units (ADUs), and parking and driveway standards. Staff scheduled a community open house for March 26 and said a draft must be ready for Commerce review in about 10 days; the commission will return April 14 for a workshop and the city council will be briefed later in the process.

Why it matters: The code changes are intended to comply with the state law that requires jurisdictions to allow middle-housing types on lots currently zoned for single-family houses. The decisions commissioners make on metrics such as lot coverage, FAR, setbacks and parking will shape how much and what type of housing — townhomes, duplexes, small cottages, stacked flats or ADUs — can be built in Mountlake Terrace and affect the relative feasibility and market price of new units.

Consultants opened by asking for policy direction rather than presenting final rules. "Today our goal is to seek more guidance on some of the housing types and initial standards," Mackenzie, a consultant to the project, told the commission. Heidi Oian, an architect and urban designer with the consultant team, summarized the firm's draft approach: "So tonight, we're going to propose initial development standards," she said, then walked commissioners through tables for lot area, unit counts per lot, lot coverage, height and setbacks.

Key proposals and findings presented - Minimum lot area: Staff proposed keeping the city's current lowest residential minimum of 4,800 square…