In Seattle, both attached (AADU) and detached (DADU) accessory dwelling units are permitted on lots where single-family dwellings are allowed. Seattle+2Seattle+2 Number of units per lot: Up to two ADUs (in addition to the primary dwelling) are allowed on one lot. These can be any combination of attached and detached units. Seattle+2Building Connections+2 Maximum size: The gross floor area of an ADU may not exceed 1,000 square feet . For a DADU in many zones the same 1,000 s
