Accessory Structures in Bothell, WA (2026)
3 verified accessory structures rules for Bothell, Washington, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
In the City of Bothell, Washington, BMC 12.14.135 allows two accessory dwelling units per lot, each up to 1,200 square feet. Detached units are capped at 30 feet in height, or 33 feet over an existing accessory structure, and unpermitted units must apply for city approval and a building inspection.
Bothell Accessory Dwelling Unit Rules
Some RestrictionsBothell Municipal Code § 12.14.135
Accessory dwelling units are permitted subject to the following requirements: A. Two accessory dwelling units are allowed per lot. B. One accessory dwelling unit in any configuration is allowed on a lot developed with middle housing. C. One accessory dwelling unit is allowed on lots designated with critical areas or their buffers. D. The size of an accessory dwelling unit shall be limited as fo...
ADU Impact Fees
In the City of Bothell, Washington, BMC 12.14.135(G) bars the city from assessing impact fees on an accessory dwelling unit that are greater than 50 percent of the impact fees imposed on the principal unit. The transportation impact fee schedule in BMC 17.045.070 lists a separate ADU rate.
Bothell ADU Impact Fee Cap
Light RestrictionsBothell Municipal Code § 12.14.135(G)
G. The city will not assess impact fees on the construction of accessory dwelling units that are greater than 50 percent of the impact fees that would be imposed on the principal unit.
Shed & Carport Rules
In the City of Bothell, Washington, BMC 12.14.130 limits accessory buildings in residential zones to five percent of the lot area and to 20 feet in height or the height of the primary building, whichever is less. Metal buildings in a different style are banned above 120 square feet, and rear setbacks are five feet.
Bothell Shed and Accessory Building Size Rules
Some RestrictionsBothell Municipal Code § 12.14.130
Accessory buildings and structures within residential zone classifications, including but not limited to storage buildings and detached private garages, shall maintain the same residential character of the primary structure, shall cover a maximum of five percent of the lot area, and shall have an exterior height no greater than 20 feet or the height of the primary building or structure, whichev...
Looking for King County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Bothell city rules.
Accessory Structures in King County →