Accessory dwelling units (ADUs) are small, secondary homes located on the same lot as an existing home. In Seattle, we allow both attached and detached ADUs, subject to certain rules (see these guidelines to learn more). ADUs offer several opportunities for Seattle residents by:
  • Creating new places to rent in high-opportunity neighborhoods
  • Allowing their owners to generate income
  • Supporting the housing needs of a range of households, including families with children, older adults downsizing or aging-in-place, multigenerational households, and people with disabilities.

Question Title

The process to create an ADU can sometimes feel complex or intimidating. To simplify and streamline permitting, the City of Seattle is developing pre-approved construction plans for detached accessory dwelling units (DADUs), often called backyard cottages. Using a pre-approved DADU plan will provide a faster, easier, and more predictable design and permitting process.

This fall, we will ask the design community to submit DADU designs that the Seattle Department of Construction and Inspections (SDCI) will review and pre-approve. But first, we want to hear your ideas for design principles we should encourage through this process.

This survey takes about 15 minutes to complete. Your responses will inform how we evaluate the design submissions. Thank you for taking this time to support this process. To learn more, read our summary.

Information provided in this survey is considered a public record and may be subject to public disclosure. For more information, see the Public Records Act, RCW Chapter 42.56. To learn more about how we manage your information, see our Privacy Statement at