Mountlake Terrace planning panel advances draft middle‑housing code; sends draft to state review

The Mountlake Terrace Planning Commission reviewed draft middle‑housing development code amendments at its April 14 meeting and heard consultant findings on which housing forms are most likely to be built under the new rules. City planning staff told the commission the draft has been submitted to the Washington State Department of Commerce for the start of a 60‑day review period.

The discussion focused on feasibility research from Echo Northwest, draft district and design standards prepared by city planning staff, and a set of public‑benefit “flexibilities” that would give developers extra height, setback or lot‑coverage allowances in exchange for public benefits such as affordable units, on‑site tree retention and mid‑block connections or alley dedication.

Becky Hewitt, a consultant with Echo Northwest, summarized a market feasibility analysis using “residual land value” metrics and test fits on a typical 7,200‑square‑foot lot. She said the analysis showed two clear winners in current market conditions: splitting a lot into two detached houses or fitting six townhouses. “The taller the bar, the more likely they are to be successful in moving forward with development and to actually choose to advance it and be able to secure a property,” Hewitt said, describing how increased unit counts raise feasibility margins.

Echo Northwest’s findings informed several draft code choices presented by planning staff, including lot coverage, height relationships between front and rear yards, and a menu of bonuses. Planning staff proposed an affordability bonus tied to the city’s MFTE program; Heidi, a city planning staff member leading the code walkthrough, said, “The affordability levels themselves the affordability levels themselves live in Title III. That’s where your MFTE program lives.” Under the draft, an affordability bonus would increase allowable lot coverage and height when a specified share of the project’s units is kept affordable under the MFTE rules.

Other proposed public benefits that would generate flexibility include on‑site tree retention, mid‑block pedestrian connections or alley dedications, and sustainable building measures (for example, allowing wall assemblies to encroach up to eight inches into setbacks to permit continuous exterior insulation). The draft specifies that mid‑block connections would be required on blocks 300 feet or longer, with a 20‑foot corridor and a minimum 10‑foot paved path for walking and bicycling; alleys qualifying for bonuses would need to be 20 feet wide and meet engineering standards before dedication to the city.

The commission discussed design and scale controls intended to keep new middle housing compatible with neighborhood character. Staff proposed limits on building width and depth for the different housing types (singles, “slots”/townhouses, rows, stacks, and courts), articulation and modulation requirements for facades, and a rule that habitable rooms must represent a minimum share of the linear frontage visible from the street (the draft sets a 50% benchmark or a minimum window area). Commissioners pressed staff for clearer, objective modulation measures and suggested adding more local precedent images to the design chapter.

A range of numeric draft standards were discussed in detail: baseline lot‑coverage tiers that step up with unit count (staff cited examples such as roughly 30% for single units, 40% at ~4 units, and up to 60% where 20% of units are affordable), rear‑yard heights set by the 20% rear depth rule, and parking ratios starting at 1 stall per unit and dropping to 0.75 in the highest‑density zone (R‑4) with additional reductions tied to the affordability or tree/connectivity flexibilities. Staff also described a driveway rule that sets curb‑cut width at 12 feet per 50 feet of street frontage and asked the commission whether guest‑parking minimums (the draft lists 1 guest stall per 20 units for developments over 20 units) are adequate.

Commissioners raised practical concerns that matched consultant findings: stacked rentals and small multifamily (fourplexes/sixplexes) were less feasible in many sites without extra incentives, so the code’s controls and bonuses will likely influence which housing types the market builds. Commissioners also urged staff to consider procedural and financial tools outside the zoning code— such as scaled impact fees for smaller units or housing action‑plan incentives—to make cottage clusters and stacked rental products more competitive.

Staff closed by outlining next steps. The draft middle‑housing chapters were filed for Commerce’s 60‑day review and staff said they will continue developer interviews, hold focused outreach, and return to the commission with refinements before forwarding recommendations to the City Council. Planning staff and the consultants told the commission they would also prepare a summary of “what we heard” for council review and continue to change numbers and definitions as the code and design standards are refined.

The commission did not take any formal votes on code adoption at the April 14 meeting; members provided direction and requested more detailed, objective modulation and transparency standards in the design chapter, and asked staff to refine parking, lot‑coverage and bonus mechanics before the next review.

Background and why it matters: Mountlake Terrace’s draft middle‑housing code is intended to implement state middle‑housing legislation and local housing goals by allowing a broader range of house‑scale and small multifamily types in residential zones while directing where and how higher densities are built. The rules and bonuses under consideration will affect how many units developers can fit on typical lots, how projects are designed, where parking and service access are located, and what public benefits (affordability, tree retention, pedestrian connections) are required to secure larger envelopes.

What to watch next: staff and consultants plan developer interviews and focused outreach in the coming weeks, the City will package a revised draft for Council review, and the Department of Commerce’s comments from its 60‑day review are expected to guide additional edits before formal public hearings and any final code adoption process.