Accessory Structures in Federal Way, WA (2026)
5 verified accessory structures rules for Federal Way, Washington, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Federal Way allows up to 2 ADUs per single-family lot under FWRC 19.200/19.265, updated for WA HB 1337 (2023). Max 1,000 sq ft each, attached or detached. Owner-occupancy is no longer required.
Federal Way ADU Rules Under HB 1337
Few RestrictionsShed Rules
Federal Way exempts one-story sheds up to 200 sq ft from building permits under FWRC 13.15 and WAC 51-16-080. Larger sheds, electrical/plumbing work, or critical-area locations need permits. Zoning setbacks always apply.
Federal Way Shed Rules and Permit Thresholds
Few RestrictionsGarage Conversions
Garage conversions in Federal Way require building permits under FWRC 13.15 and 13.22. Habitable conversions trigger egress, insulation, smoke/CO, and utility permits. Conversions to ADUs are allowed under HB 1337.
Federal Way Garage Conversion Rules
Some RestrictionsCarport Rules
Carports in Federal Way are accessory structures under FWRC Title 19 and generally need permits if over 200 sq ft. Setbacks, height, and lot-coverage apply. Fabric carports in front yards are often restricted.
Federal Way Carport Rules
Some RestrictionsTiny Homes
Federal Way allows tiny homes on permanent foundations as ADUs or primary dwellings under FWRC 19.200 and 19.265. Tiny homes on wheels are RVs and cannot be permanent dwellings on residential lots.
Federal Way Tiny Home Rules
Some RestrictionsLooking for King County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Federal Way city rules.
Accessory Structures in King County →