Mountlake Terrace planning commission recommends wide-ranging middle-housing code update

The Mountlake Terrace Planning Commission on May 27 recommended that the City Council adopt a package of ordinances to implement middle-housing zoning, design standards and related parking and affordability rules, saying the changes will go to a council hearing on June 26.

The commission's motion — approved with no recorded opposing votes — would repeal and replace portions of the Mountlake Terrace Municipal Code (MTMC) and add a new MTMC chapter on middle-housing affordability. Commissioners attached several technical modifications before forwarding the package to council, including a driveway-width clarification (a 12-foot minimum at the curb cut and a 20-foot maximum per 60 feet of linear lot frontage), a requirement that applicants identify the housing form type on permit applications, a clarification that accessory dwelling units (ADUs) are allowed per lot, a side-yard minimum of no less than 3 feet, and a requirement that mid-block pedestrian/vehicle connections need not be grade-separated but must use different paving to emphasize pedestrian use.

Why it matters: The package implements state middle-housing laws and sets new local rules on scale and design for single-family and multifamily development in Mountlake Terrace, including how the city will allow bonuses for affordable units, tree retention, mid-block connections and other public benefits. The changes affect how many units can be built on typical Mountlake Terrace lots, what those buildings can look like, and when parking or ADUs must be provided.

Key provisions and deliberations

- Scale controls and bonuses: The draft code relies on floor-area-ratio (FAR) as the primary scale control, with by-right FAR tiers and higher FAR available through bonuses. Officials described example FARs presented in the hearing: 0.5 FAR for a single-family house, 0.6 for two units, 0.8 for three units, and up to 1.4 by right in higher-density zones; bonused FARs rise to 1.8 in R-3 and 2.4 in R-4 where public benefits are provided. Bonuses considered include affordable units, on-site tree retention, sustainability certification, mid-block connections, improved parking courts and shared driveways.

- Density and lot coverage: Staff proposed minimum lot sizes consistent with existing RS 4,800 zoning and density rules aligned with state HB 1110 middle-housing requirements. Lot-coverage maximums would increase across zones (examples given: 45% in R-1 to 65% in R-4) and a 5% lot-coverage bonus was proposed to accommodate additional units. Presenters said the city could consider removing lot coverage as duplicative if FAR and other limits are retained, but recommended keeping the current figures as they are relatively easy to comply with.

- ADUs and unit size: The draft aligns ADU rules with state HB 1337: up to two ADUs allowed per lot (attached or detached), ADUs may be up to 1,000 square feet, do not require owner occupancy, and count toward density. Staff confirmed ADUs remain allowed across the residential zones and noted a slide typo ("20 square feet") that should read 200 square feet for a different standard; the code text itself was checked and staff said the ordinance language is correct.

- Parking and driveways: The draft moved off-street parking language into MTMC chapter 19.125 and updated requirements in light of recent state laws. Staff said the proposed baseline is one parking stall per unit, with statutory exceptions: no required parking for ADUs, projects near transit, and qualifying affordable projects; guest parking may not be required. The commission discussed driveway widths at length; commissioners and staff agreed to a technical modification setting a 12-foot minimum curb cut and a maximum of 20 feet per 60 feet of frontage (the motion sent to council asks staff to include that technical correction in the ordinance language).

- Mid-block connections and parking courts: The draft incentivizes mid-block pedestrian and bicycle connections with substantial FAR bonuses (half-block connections and full-block connections received different bonus amounts in the presentation). The commission debated whether pedestrian/vehicle shared paths must be grade-separated; the commission ultimately asked that grade separation be optional (not required) for mid-block connections that allow vehicles, but that the paving materials be different to signal pedestrian priority. Improved parking courts were described as shared, pedestrian-friendly vehicle courts that must serve at least two units and meet design standards addressing surfacing, lighting, windows and personalization areas.

- Design standards: A new MTMC chapter 19.32 would set neutral style standards for orientation, ground-floor uses, facade modulation and articulation, transparency, unit entries, open space and utilities. Examples discussed include requiring at least 50% habitable frontage along street-facing facades, minimum transparency (25% windows) on street facades, modulation or articulation requirements based on facade width, and limits on principal cladding materials.

- Affordability: The draft's affordability bonus is informed by HB 1110 and is structured so that rental units qualifying for the bonus must be affordable at 60% of area median income (AMI) and ownership units at 80% AMI, with the city adding a new MTMC Chapter 3.96 to track those rules. Staff acknowledged implementation challenges, in part because state law calls for long-term affordability monitoring; a staff member said, "I don't believe so, but we're also mandated to provide for this," when asked if the 50-year tracking the state calls for is practical for a smaller jurisdiction.

What commissioners and public speakers said

- Heidi Oyan, architect and urban designer with Methune, summarized the draft and told commissioners, "It's been a pleasure working with you and staff on these, and I'm looking forward to this discussion and comments from the community." Oyan presented the FAR tables, bonus structure and design standards that formed the basis of the hearing.

- Mackenzie Visser (Echo Northwest) and Sandra Gergis (Methune) joined the presentation and answered technical questions during the Q&A.

- In public comment, local developer Dwayne Landsberg urged the commission to keep the rules implementable and to prioritize speed and incentives: "If we want it affordable, we need to build more housing types, and we need to build it fast," he said, adding that overly prescriptive standards and long permitting times undermine affordability.

Votes and next steps

The commission voted to forward the ordinance package to city council with the technical modifications described above. The motion as entered into the record asked staff to include the driveway-width change and the other clarifications discussed in the hearing; the motion carried with no recorded opposing votes. If council follows the commission's recommendation, the ordinances are scheduled for a City Council hearing on June 26, 2025. Staff said additional zoning changes and a housing action plan will follow later in the year.

Ending

Commissioners and staff said they expect to revisit some numeric standards after the code is in place and early projects begin to test the rules. For now, the package moves to the City Council with several technical clarifications attached and with a June 26 hearing date on the calendar.