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

Garage conversions in unincorporated San Bernardino County are processed as accessory dwelling units under Development Code Chapter 84.01 together with California ADU law (Gov. Code 66310 et seq.). Section 84.01.060(f)(1) exempts garage conversions from setbacks: no setback is required for an existing garage that is converted to an ADU, and a setback of no more than five feet from the side and rear lot lines is required for an ADU constructed above a garage. Because of fire-safety concerns, the code expressly notes that garage conversions and ADU additions above a garage are not exempt from roadway setback requirements in the Mountain Region. Under Section 84.01.060(f)(3), ADUs built within the existing space of a dwelling or accessory structure (which includes garage conversions) are not required to install new or separate utility connections and are not subject to a separate connection fee or capacity charge. Parking eliminated by a garage conversion need not be replaced, consistent with state ADU law. The County's ADU Standards table allows conversions with no minimum unit size beyond California Residential Code requirements and treats them ministerially, with a 60-day approval timeline. Owners must still obtain building, drainage, egress, and fire approvals before a permit is issued.