Mendocino County, CA Accessory Structures: Shed Rules (2026)

In unincorporated Mendocino County, storage sheds are treated as detached accessory buildings, defined in the Zoning Ordinance as subordinate structures incidental to the main use that may not contain sleeping quarters or kitchen facilities. Following the California Building Code adopted by the County, a one-story detached accessory structure is exempt from a building permit if its floor area does not exceed 120 square feet; structures of 120 square feet or larger require a building permit. A building-permit exemption does not waive zoning rules, so sheds must still meet district setback, height and lot-coverage standards. Under the inland yard regulations at Section 20.152.015, a detached storage shed, detached garage, or similar detached accessory building not exceeding 15 feet in height at the ridge and 500 square feet of floor area may observe a reduced 5-foot setback from interior side and rear property lines. Larger or taller accessory buildings must meet the full setbacks of the underlying zoning district. Agricultural accessory buildings such as barns, stables and chicken houses must be set back not less than 50 feet from any property line and not less than 40 feet from any dwelling. In the Coastal Zone, parallel standards apply and exterior changes may require a Coastal Development Permit. Confirm requirements with Planning & Building Services.