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

Colusa County Code Chapter 44 (Zoning Code) defines an 'accessory building or structure' as 'a detached building, the uses of which are secondary, supportive, and/or subordinate to the primary structure or principal permitted use on a parcel,' noting that an accessory dwelling unit is not an accessory building (Sec. 44-0.10, Definitions). A garden or storage shed is therefore regulated as an accessory structure under the development standards for the applicable zone. In the residential zones (R-R, R-1, R-2, R-3, R-4), the development-standards table at Section 44-2.30.20 sets minimum accessory-structure setbacks of 20 feet in the front yard, 5 feet in the rear yard, and 5 feet on the interior side in the front 50% of the lot, reduced to 3 feet in the rear 50% of the lot. A table footnote further provides that 'Detached accessory buildings must be 5 feet from any building.' Maximum height and lot-coverage limits for the zone also apply. A building permit is administered separately by the county Building Division under Chapter 5 (Building Code); the zoning setbacks apply even where a very small structure might be exempt from a building permit under the California Building Code. Standards in the agricultural and other zoning classifications differ, so owners should confirm the requirements for their specific zone with Colusa County Planning & Building before placing a shed.