ADU Reform Moves Forward in Seattle

A sweeping reform of Seattle's current accessory dwelling unit (ADU) rules is currently underway. Proposed legislation sets the stage for an ADU boom to potentially match Vancouver and Portland.

1 minute read

June 11, 2019, 11:00 AM PDT

By Philip Rojc @PhilipRojc


Accessory Dwelling Unit

Nicolás Boullosa / Flickr

Legislation to reform the city's ADU rules is making its way through Seattle City Council. "The proposed legislation heard in committee addresses eight key policy areas for attached and detached accessory dwelling units [...], ranging from unit size and parking requirements to owner-occupancy requirements and height limits," Stephen Fesler writes. "If reform is made, the legislation could help spur a new cottage industry in accessory dwelling unit (ADU) building."

Fesler discusses a number of rule changes in the proposed ordinancesubject to amendmentincluding the following:

  • Increased number of unrelated persons allowed per lot
  • Larger allowed ADU size
  • Higher ADU height limits
  • ADUs may be allowed to cover a larger percentage of lot area
  • Elimination of off-street parking requirements for new ADUs
  • Removal of owner occupancy requirements
  • New floor-area ratio (FAR) limits to combat mansionization

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