Accessory Dwelling Unit - SDCI | seattle.gov

This Seattle Department of Construction and Inspections (SDCI) page explains the rules and permits required for accessory dwelling units (ADUs), which are separate living spaces within a house or on the same property. ADUs must be legally permitted through a permit process and comply with size, location, and code standards. The ADUniverse website offers pre-approved building plans for detached ADUs to speed up the permitting process.