PCD 2024-05-13 Item 1A - Discussion - Housekeeping Amendments to Accessory Dwelling Units (ADUs) Standards

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City of Tukwila ThomasMcLeod, Mayor INFORMATIONAL MEMORANDUM TO:Planning and Community Development FROM:Nora Gierloff, DCD Director BY:Isaac Gloor, Associate Planner CC:ThomasMcLeod DATE:May 13, 2024 SUBJECT:Title 18 Housekeeping: Accessory Dwelling Units ISSUE Minor housekeeping amendments to Title 18 to updateAccessory Dwelling Unit development standards. BACKGROUND In November of 2023, the City Council approved zoning code amendments that altered the development standards for Accessory Dwelling Units (ADUs) to comply with the recently passed State Law, known during development as HB 1337. These amendments allow for all parcels where Single-Family Homes are permittedto now develop up to two ADUs, in either attached or detached form, without owner occupancy and, if near frequent transit,without additional parking. Parking standards for single-family homes were not changed, and ADUs are still subject to most of the samedevelopment standards assingle-family homes are, including setbacks and impervious surface limits.While the majority of the changes made were amendments to TMC since the DISCUSSION Below is a summary of the identified code sectionsand proposed changes: TMCTable 18-6:Land Uses Allowed byDistrict o Issue:State law requires that Tukwila permit ADUs anywhere that the City permits Single--Family Homes are districts: Low-Density Residential, Medium-Density Residential, and High-Density Residential. The land use table currently permits ADUs within those districts. However, Tukwila also permits single-family homes within several other districts, including the Mixed Use Office(MUO), Office(O), Residential Commercial Center(RCC), and Neighborhood Commercial Center(NCC)districts. As Table 18-6 does not show that ADUs are permitted within those districts, Tukwila could not allow a new ADU to be established within them. This leaves Tukwila out of compliance with the requirements of State Law. o Suggested Change:Staff proposes to amend TMC Table 18-6 to include ADUs as permitted accessory uses within the MUO, O, RCC, and NCC zoning districts. While this would permit ADUs within 4 additional zoning districts than what is currently permitted, the impact is expected to be minor, as these districts do not currently contain many eligible properties and are unlikely to in the future. TMC 18.50.220(B)(3):Accessory Dwelling Unit (ADU) Standards; General Standards o Issue: This code section establishes the maximum size of detached ADUs, which, as required by the State, is set at 1000 square feet. However, it also 1