On Aug. 15, 2006, Mayor Greg Nickels signed Ordinance 122190 that allows detached accessory dwelling units (DADUs) in single family zones in Southeast Seattle (south of I-90 and east of I-5). The ordinance becomes effective on Sept. 14, 2006.

A recent community-led task force in Southeast Seattle developed an action agenda that recommends DADUs as a way to help housing affordability and to help existing homeowners stay in Southeast Seattle. Other community organizations in the area also support DADUs.

Eligible lots must have at least 4,000 square feet of area. The DADU standards maintain existing restrictions on lot coverage and rear yard lot coverage currently in single family zoning. As with existing accessory dwelling unit rules, owner occupancy and an off-street parking space are required, and there are limits on the size of the units. In the case of detached ADUs, both the overall size and height of the structure are limited based on the size of the lot to help ensure they do not overwhelm the area around it.

As a result of this legislation, CAM 116, Establishing a New Accessory Dwelling Unit is being replaced by CAM 116A, Establishing an Attached Accessory Dwelling Unit and CAM 116B, Establishing a Detached Accessory Dwelling Unit. Also, CAM 606, Illegal Dwelling Units has been updated.