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Cities Act to Embrace Various Legislation

January 31, 2024

The 2023 legislative session in Olympia was dubbed the “Housing Session” based on numerous bills passed by legislators to increase the supply of housing throughout the state. Now, cities are working to implement the new legislative mandates, with early action focused on Accessory Dwelling Units and Unit Lot Subdivisions (also known as Zero Lot Line Units):


The city of Tukwila is moving forward to amend Title 17 of the city code to address Unit Lot Subdivisions as follows:

“Sites developed or proposed to be developed with townhouses, cottage housing, compact single-family, accessory dwelling units, or zero-lot line units may be subdivided into individual unit lots. The development (as a whole) shall meet development standards applicable at the time the permit application is vested. Any private, usable open space for each dwelling unit shall be provided on the same lot as the dwelling unit it serves.“

Additionally, Title 18 is being amended to make it easier to site Accessory Dwelling Units. New code language provides:

“Accessory dwelling unit means a dwelling unit located on the same lot as a single-family housing unit, duplex, triplex, townhome, or other housing unit”…and…“Single-family dwelling” means a building, modular home or new manufactured home, designed to contain no more than one dwelling unit plus two accessory dwelling units.

“Additionally, the City’s code includes several additional technical specifications involving increasing the number of ADUs on a parcel, maximum unit size, increased height, and lot coverage of ADUs, as well as adding authorization for tandem parking.”

Together, these amendments address both increased “ownership” opportunities, as well as increased “housing supply” - both of which are badly needed in the Central Puget Sound Region.


In the city of Enumclaw, city staff and the Planning Commission, have forwarded to the City Council recommendations that Enumclaw modify its development regulations for Accessory Dwelling Units to include the following:

  • Updated definitions, consistent with House Bill 1337 passed in 2023
  • Removal of Owner Occupancy requirements
  • Allow ADUs to be sold as condominiums
  • Increase the maximum size of an ADU 25% (from 800 to 1000 square feet of gross floor area)
  • Allow two ADUs on any lot in most configurations (two detached, two attached, or mixture)
  • Increase maximum ADU heights from 18’ to 24 feet
  • Eliminate the requirement that owners provide an affidavit that they reside on the premises, eliminate notice and hearing provisions, and eliminate pre-inspection requirements
  • Add provisions providing a path to legalize non-conforming structures, ensuring that ADUs are safe to inhabit.
  • The section regarding pre-existing ADUs has been removed as outdated; and
  • Cap impact fees at 50% of the normal impact fee for a single family home.
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