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Built by Blue Sound Construction, designed by MaKe Design, photos by Alex Hayden

Seattle City Council Unanimously Approves ADU Reform Legislation

Posted on Jul 3, 2019 in:
  • Advocacy
  • Industry Issues
  • Building Codes

The Seattle City Council voted July 1 to unanimously approve the long-awaited accessory dwelling unit (ADU) reform legislation. We’ve heard from many members that they have clients interested in building an ADU but have been awaiting the outcome of this legislation.

Recap of bill as it affects floor area ratio (FAR):

Seattle ADU reform legislation restricts FAR on a home to .5 or 2,500 SF on a 5,000 SF single-family lot. This will significantly reduce the size of new homes in Seattle. Our association strongly opposed any restrictions to FAR and was able to regain some square footage via a last minute amendment on garage exemptions. Other helpful exemptions from FAR totals include:

  • All stories, or portions of stories, that are underground
  • All portions of a story that extend no more than four feet above existing or finished grade, whichever is lower, excluding access
  • Any floor area contained in an accessory dwelling unit
  • Either up to 500 additional square feet of floor area in any other accessory structure that is not a detached accessory dwelling unit or up to 250 square feet of floor area in an attached garage

Also, the following is exempt floor area from DADU maximum size limits:

  • Up to 35 square feet of floor area dedicated to long-term bicycle parking from the maximum size requirements for a detached accessory dwelling unit (DADU)
Please contact Seattle Government Affairs Manager Aliesha Ruiz, 425.460.8204, with any questions.


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Photo courtesy Blue Sound Construction, builder; MaKe Design, architect; and Alex Hayden, photographer