Home Page
Link to Seattle Department of Construction & Inspections home page

SDCI Closures, Service Updates, and Inspection Requirements

SDCI customer service areas remain closed until further notice and continue offering services online. King County has approval from the State Department of Health to allow all private construction activities that are low-risk and adhere to strict COVID 19 Job site Requirements. The City of Seattle has issued requirements for construction projects seeking inspections. The City WILL NOT INSPECT any site that does not follow these requirements.


Summary: This Tip explains how to establish an attached accessory dwelling unit (also called an AADU or mother-in-law unit). An AADU is a room or set of rooms designed and established by permit to be a separate dwelling unit. AADUs can be located in a single-family home in the Single Family (SF) 5000, SF7200, and SF9600 and Residential Small Lot (RSL) zones. In the RSL zone they can also be located in a principal dwelling of an apartment unit, carriage or cottage house, rowhouse, or townhouse. In the lowrise (LR) zones, AADUs can be located in a single-family home, rowhouse or townhouse unit.

Date Revised: 08/13/2019

See all Tips