Burien planners map new R‑zones, outline unit limits, setbacks and bonuses tied to state law

Burien planning staff on March 12 outlined proposed housing code and zoning‑map amendments that would create three new residential zones (R1, R2 and R3), change minimum lot sizes and setbacks, and implement state middle‑housing requirements ahead of a June adoption target.

Planner Chaney Scottson told the Planning Commission the work responds to House Bill 1110 and other state rules and is intended "to expand the allowed residential housing types within our residential zones." Scottson said the city is modeling zone provisions to meet the statute’s requirements for middle housing types and bonuses tied to transit proximity and affordability.

The proposal would: set minimum lot sizes at 6,000 square feet in R1, 5,000 in R2 and 3,000 in R3; permit a baseline of three units per lot in R1 (reflecting ADU rules under House Bill 1337), and four units per lot in R2 and R3 without bonuses; reduce front‑yard setbacks from 20 feet to 15 feet in R1 and to 10 feet in R2 and R3; retain the existing 35‑foot maximum height; and vary impervious‑surface maximums so higher‑intensity zones allow greater coverage.

Scottson summarized bonus unit rules tied to state law and local policy: tiered bonus units may be added when a lot is within a quarter‑mile of a qualifying transit stop or when one or more units are reserved at specified affordability levels. Under the proposal, R2 projects could reach up to six total units if all bonuses apply; R3 projects could reach up to seven total units when two units are reserved as affordable. Scottson said the statute requires rental bonus units to serve households at 60 percent area median income (AMI) and owner‑occupied bonus units at 80 percent AMI.

Commissioners pressed staff on how the rezoning interacts with mapped critical areas, the shoreline and the city’s forthcoming critical‑areas update. Scottson emphasized that updates to Title 19 (zoning) would not override the city’s critical‑areas protections or the Shoreline Master Program: "If it is an encumbered site, they need to get through those restrictions and limitations first by doing a critical areas report," she said. Commissioners noted some parcels designated R3 sit within mapped landslide or stream buffers and asked staff to run parcel‑level summaries.

Parking and street impacts drew repeated questions. Scottson said the state statute exempts projects within a quarter‑mile of transit from required parking; outside that buffer, projects must provide one parking space per dwelling unit. She also noted existing local tools that can reduce parking needs, including allowances for tandem parking and provisions that could remove parking requirements when tree‑preservation rules or other constraints make on‑site parking infeasible.

Other discussion points: several commissioners asked the office to model typical lot scenarios to show massing, tree impacts and stormwater implications for the proposed impervious‑surface maximums; staff said they have engaged consultants to run feasibility studies and would return with visual examples and comparisons to nearby jurisdictions. Commissioner Sam Ostrander asked staff to evaluate converting a Seahurst neighborhood R1 designation to R2; the commission voted to ask staff to study that change.

Why it matters: the changes are meant to comply with state middle‑housing mandates while steering growth to areas with transit and services. Commissioners repeatedly emphasized that mapped critical areas, tree preservation, stormwater controls and the Shoreline Master Program remain limiting layers that will affect how many units are feasible on any given parcel.

The Planning Commission will continue the zoning discussion at upcoming meetings; staff said the goal is to forward adopted code amendments to City Council by June.