Burien planners introduce unit‑lot subdivisions; signal support to raise short‑plat cap

Burien Planning Commission members heard an introduction to unit‑lot subdivisions at their Feb. 12, 2025, meeting and gave informal direction to staff to draft code changes that would allow more units to be created administratively through the short‑plat process.

Planning staffer Chase Gatson told the commission the unit‑lot subdivision process would allow multiple housing units on a single parent parcel to be subdivided into individual unit lots to enable fee‑simple ownership. “Unit lot subdivision is to allow multiple housing units on a single parcel, to be subdivided into individual unit lots for sale to individual owners,” Gatson said.

The briefing explained how Burien currently treats lot division: short plats apply when a single parcel is split into four or fewer lots and use an administrative review; subdivisions or “long plats” are required for five or more lots and go to the city council. Gatson said state law allows cities to adopt short‑plat limits up to nine lots, and Burien is one of the few nearby jurisdictions that still caps short plats at four.

Why it matters: staff presented unit‑lot subdivisions as a tool paired with the city’s pending middle‑housing code and map amendments. The change is intended to make townhome‑style and other attached middle‑housing types feasible for fee‑simple ownership, expand homeownership options, and reduce permitting time and cost compared with long‑plat review.

Details discussed included dimensional and design implications, parking and traffic fees, utilities and shared‑area maintenance, and ownership models. Gatson noted unit‑lot approvals let the parent lot meet zoning standards while allowing internal unit lots to be configured in ways that would not individually meet standard setbacks. He also said accessory dwelling units could be sold as separate unit lots where appropriate.

On parking and fees, staff said the draft approach would generally require one off‑street parking space per unit, with existing statutory exceptions for units near transit. Director of Community Development Liz (last name not specified in the transcript) reported ongoing state legislative proposals that could change local parking rules: “That one would actually require one parking stall for every two units to be the maximum that a city could require for off‑street parking,” she said, referring to a bill under consideration at the state legislature.

Commissioners raised concerns about potential circumvention of more intensive subdivision review and about large parent parcels being converted into a modest number of large single‑family lots using the short‑plat process. Commissioner Sam Ostrander asked whether the city could limit whether units allowed under a short plat are attached or detached; staff replied that unit‑lot subdivision is the specific tool for attached, townhome‑style ownership and that regulation of allowed housing types is part of the broader middle‑housing work.

Commissioners pressed staff for clearer visual materials comparing short plats, unit‑lot subdivisions and long plats. Several commissioners asked staff to return with a side‑by‑side table and example lot sizes showing how many units would fit on common Burien parcel sizes under the proposed changes.

Informal direction and next steps: the commission took an informal thumbs‑up poll and multiple members indicated support for raising Burien’s short‑plat threshold from four to nine units to align with state allowances and neighboring cities. Commissioners also asked staff to research whether the city could legally apply a maximum parent‑lot size or other controls to prevent large lots being divided in ways that defeat the city’s density and design goals; staff agreed to consult legal counsel and return with findings.

Staff said the unit‑lot subdivision code language will be coordinated with the Title 19 housing code and map amendments, and that staff will bring a draft ordinance and clearer graphics back to the commission. The commission’s advance calendar shows a public hearing on related temporary‑encampment provisions on Feb. 26 and a March 12 meeting that will include the Title 19 housing draft code amendments and the unit‑lot subdivision draft code.

No formal vote or ordinance adoption occurred at the Feb. 12 meeting; commissioners gave informal direction for staff to prepare draft code changes and research legal questions.