Accessory Structures in Seattle, WA (2026)
2 verified accessory structures rules for Seattle, Washington, sourced directly from the municipal code and official government pages.
Verified from official government sources
Shed & Carport Rules
SMC 23.44.090(G) lets garages and carports sit in a required setback under specific conditions: a front-setback garage is capped at 300 square feet and 14 feet wide for one space, or 600 square feet and 24 feet wide for two, and a rear-setback garage must stay 5 feet off the rear line.
Seattle Garage and Carport Setback Rules
Some RestrictionsSeattle Municipal Code § 23.44.090(G)
G.Garages and carports1.Garages and carports may be located in a setback where parking is allowed in a setback as provided in subsections 23.44.160.D.4 and 23.44.160.D.5.2.Garages and carports may be located in a required side setback that abuts the rear or side setback of another lot if:a.The garage or carport is a detached structure and extends only into that portion of a side setback that is...
Tiny Homes
Seattle allows tiny houses on permanent foundations as Detached Accessory Dwelling Units (DADUs) under SMC 23.42.022 and SMC 23.44.041, subject to the same code as any DADU. Tiny houses on wheels (THOWs) are treated as recreational vehicles and may not be used as residences in city residential zones. Sanctioned tiny house villages exist only as transitional encampments under SMC 23.42.054.
Seattle Tiny Home Rules
Some RestrictionsSeattle Municipal Code 23.42.022 — Accessory Dwelling Units (Tiny houses on wheels vs. DADUs)
Accessory Dwelling Unit — An accessory dwelling unit (ADU) is a separate living space within a house or on the same property as an existing or proposed house. These units may not be subdivided from the main house and are not legal unless they have been established through a permit process. A legally permitted unit in the home is called an attached accessory dwelling unit (AADU). A legally permi...
Looking for King County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Seattle city rules.
Accessory Structures in King County →