Colusa County, CA Accessory Structures: Tiny Homes (2026)

Colusa County Code Chapter 44 (Zoning Code) directly addresses tiny homes in its definitions (Sec. 10). It provides that 'a tiny home is a structure that meets the definition of a tiny house in Appendix Q of the 2019 California Residential Code,' and that a tiny home (park trailer) located outside of a county- and state-approved mobile-home and/or special-occupancy park 'is considered an approved type of accessory dwelling unit if the following criteria are met': (1) all utilities are connected to county-approved systems under an issued county permit; (2) the wheels and tongue are removed and the structure sits on a county-approved foundation system for which a building permit has been issued; (3) the exterior includes typical residential design elements (sloped roof, roof material, siding, window details) so it resembles a residential structure and not a recreational vehicle, to the satisfaction of the community development director; and (4) skirting is installed that screens the underside chassis and foundation.

10 also apply (one unit per parcel, kitchen/bath/separate entrance, size and setback limits), and current California ADU law (Government Code Sections 66310-66342) requires ministerial approval of a conforming unit. A tiny house on wheels kept as an RV/park trailer (wheels and tongue not removed, no permanent foundation) does not satisfy these criteria and is not an approved dwelling. Confirm details with Colusa County Planning & Building.