City Weighing Options for Regulating Accessory Dwelling Units

Posted: 01 Jun 2018 By: Kris Ilgenfritz

On May 10, the city of Seattle released its draft environmental impact statement for attached dwelling units (ADUs). ADUs were formerly known as backyard cottages and detached ADUs (DADUs) were formerly known as backyard houses.

Here is an overview of the three alternatives that the city is proposing for changing land-use codes that apply to these units. To see the full document, including a table comparing components of the alternatives. go to www.seattle.gov/council/adu-eis and click on “Read the Draft EIS.”

Alternative One - Lots in single-family zones could have one ADU or one DADU but not both. One off-street parking space would be required for an ADU or DADU unless the lot is in an urban village. The owner would have to occupy the main house or detached unit at least six months out of the year. Minimum lot size would be 4,000 sq. ft. Maximum gross floor area would be 1,000 sq. ft. for an ADU and 800 sq. ft. for a DADU, including garage and storage areas.

Alternative Two - Lots in single-family zones could have an ADU and a DADU. Off-street parking and owner occupancy of the main house or detached unit would not be required. Minimum lot size would 3,200 sq. ft. Maximum gross floor area would be 1,000 sq. ft. for an ADU and 1,000 sq. ft. for a DADU, excluding garage and storage areas. An ADU or a DADU could exceed 1,000 sq. ft. if the portion of the structure in which the unit is located existed on Dec. 31, 2017, and if the entire unit is located on one level.

Alternative Three - Lots in single-family zones could have an ADU and a DADU or two ADUs. No off-street parking would be required for lots with one ADU. One off-street parking space would be required for lots adding a second ADU. The owner would need to occupy the main house or one of the detached units at least six months out of the year.

Minimum lot size would 3,200 sq. ft. Maximum gross floor area for either type of accessory unit would be 1,000 sq. ft, excluding garage and storage areas. An ADU or a DADU could exceed 1,000 sq. ft. if the portion of the structure in which the unit is located existed on Dec. 31, 2017, and if the entire unit is on one level.

FCA will post notes at www.fauntleroy.net as soon as possible after the public open house planned for May 31. The city will be accepting public comments through June 25: online at www/seattle.gov/council/adu-eis, by email to adueis@seattle.gov, or by letter to Aly Pennucci, PO Box 34025, Seattle 98124-4025.

The city plans to issue its final environmental impact statement by late summer/early fall.

Note: A version of this article first appeared in the June 2018 edition of Neighbors.