Tukwila: Title 18 Amendments
The City of Tukwila has proposed comprehensive amendments to Title 18 of the Tukwila Municipal Code (TMC) to comply with recent state legislation, most notably HB 1110 concerning middle housing, with a compliance deadline of June 30, 2025. Scheduled for a hearing on April 24, 2025, under file numbers L25-0032 and E25-0009, these updates aim to streamline regulations and foster housing development that aligns with community objectives. The notification of this hearing was published in the Seattle Times and on the city's website on April 10, 2025. An environmental determination will precede City Council consideration.
The proposed changes encompass several key areas. Regarding housing allowances and development standards, the city intends to permit eight of the nine middle housing types, excluding only sixplexes. A significant consolidation is proposed, merging the Low Density Residential and Medium Density Residential zoning districts into a new Community Residential (CR) zone with unified development standards. These standards vary based on proximity to major transit stops and the inclusion of affordable housing units. Outside a quarter-mile radius of a major transit stop, the CR zone would allow a minimum lot area of 5,000 square feet, an average lot width of 40 feet, and a density starting at three units per parcel, increasing with lot size up to five units. Within the transit buffer or with dedicated affordable units, the same base density applies. Notably, up to two accessory dwelling units (ADUs) would be permitted per lot and count towards the maximum density. Building footprint would be capped at 50%, and development area coverage at 75%. Setback requirements are specified for front, side, and rear yards, with allowances for front porches and alley-accessed detached ADUs. Building height is limited to 35 feet.
Parking standards are also slated for revision based on housing type. Single-family homes would see a reduction to a flat two spaces per home. No parking would be required for ADUs. For middle housing outside the half-mile transit buffer, one parking space per unit would be mandated, while no parking would be required within the buffer. Multifamily housing would also see reduced requirements, with 0.75 spaces per studio and one space per unit with one or more bedrooms.
Furthermore, the proposal includes the establishment of new, simplified design standards for middle housing and single-family homes intended to be easily understood and administered without causing review delays. New definitions for specific middle housing types, consistent with state law, are also proposed. To ensure consistent application of standards throughout the TMC, references to the former LDR and MDR zoning districts will be updated, and standards will be revised to treat single-family and middle housing equally. Finally, nonconformance standards, previously applicable only to single-family housing, will be updated for consistency, and outdated regulations concerning cargo containers will be removed.
Staff analysis indicates that these amendments align with the Tukwila Comprehensive Plan and do not necessitate its modification. The expansion of middle housing and ADU allowances is expected to increase infill housing, providing diverse housing options with a scale comparable to existing single-family homes, thus limiting visual impact. Alternatives to the proposed amendments were considered, with staff noting that failure to comply with HB 1110 by the deadline would result in the city defaulting to the state's model ordinance, limiting local control. Staff believes the proposed package appropriately balances infill development with community needs. The staff report cites relevant sections of the TMC and other supporting documents. The City Council's decision will be based on consistency with the Comprehensive Plan and whether the amendments eliminate conflicts, achieve policy directives, or correct errors in the TMC.