San Benito County, CA Accessory Structures: Garage Conversions (2026)

San Benito County does not have a standalone 'garage conversion' chapter; a habitable conversion is reviewed under the accessory dwelling unit provisions of § 25.08.002, which implement state ADU law. California Government Code permits ministerial conversion of an existing garage or accessory structure into an ADU, and § 25.08.002 reflects that conversions of legally established structures are exempt from the 4-foot setback applied to new ADU construction. Importantly, § 25.07.006 provides that a detached accessory building such as a garage may not simply be converted to a dwelling without going through the ADU process. A garage converted to an ADU still requires a building permit demonstrating compliance with the California Residential Code for habitability (ceiling height, light, ventilation, egress, smoke/CO alarms) and adequate septic and water capacity, which is a significant gate on ranch and rural parcels relying on wells and septic systems. State ADU law limits when the County may require replacement parking for the spaces the garage previously provided; many conversions qualify for a parking exemption (for example, within a half-mile of transit). A non-habitable conversion (turning a garage into a workshop or storage) is handled as an alteration to an accessory structure under § 25.07.006 and must keep the building from becoming an unpermitted dwelling. Confirm the path with the Resource Management Agency before starting work.