Accessory Structures in Federal Way, WA (2026)
3 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 two accessory dwelling units per single-family lot under FWRC 19.200.180, each capped at 1,000 square feet and two bedrooms unless the ADU is attached and built inside the existing home's footprint. One parking space per unit is required, dropping to zero within a half mile of a major transit stop.
Federal Way ADU Zoning Rules
Some RestrictionsFWRC 19.200.180
1. An accessory dwelling unit (ADU) shall meet the definition outlined in FWRC 19.05.040. Minimum lot size for ADUs is based upon the minimum lot size for the existing primary dwelling unit as set forth in FWRC 19.200.010... 2. Up to two ADUs may be created per subject property. The ADUs, accessory structures and the primary dwelling unit together shall not exceed the maximum lot coverage and o...
ADU Impact Fees
Federal Way caps both transportation and park impact fees for accessory dwelling units at 50 percent of what a detached single-family home pays. The discount applies automatically when the city assesses fees at building permit issuance under FWRC 19.91.060 and 19.92.060.
Federal Way ADU Impact Fee Caps
Some RestrictionsFWRC 19.91.060(6), (7)
(6) For accessory dwelling units, transportation impact fees shall not exceed 50 percent of the transportation impact fees required for a detached single-family dwelling. ... (7) The department of community development shall not issue the required building permit until a lien has been recorded pursuant to FWRC 19.100.075(3), or the transportation impact fees set forth in the fee schedule have b...
Shed & Carport Rules
A storage shed in a required side or rear yard needs discretionary Process III approval in Federal Way, capped at eight feet high, 120 square feet, and a 10-foot facade, under FWRC 19.125.160(9). Front yards are off-limits entirely.
Federal Way Storage Shed Yard Placement Rules
Significant RestrictionsFWRC 19.125.160(9)
(9) In low and medium density residential zones, the applicant may, through process III, request approval to locate a storage shed in a required yard, except a required front yard. The city may approve the application if: (a) The proposed structure is no more than eight feet high above finished grade; (b) The maximum length of the facade of the proposed structure parallel to each property line,...
Looking for King County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Federal Way city rules.
Accessory Structures in King County →