San Bernardino, CA Accessory Structures: ADU Rules (2026)

California Government Code Sections 65852.2 and 65852.22, as amended by AB 68, AB 881, SB 9, AB 1033, AB 2221, and related legislation through 2024, require every city in California including San Bernardino to ministerially approve qualifying Accessory Dwelling Units and Junior Accessory Dwelling Units without discretionary review, public hearing, or use of subjective design standards. The City of San Bernardino ADU ordinance implements state law and allows one detached or attached ADU plus one Junior ADU on qualifying single-family parcels, and up to 25 percent of the existing unit count as ADUs on multi-family lots plus detached ADUs on multi-family parcels. Maximum sizes under state law are 850 square feet for a one-bedroom ADU and 1,000 square feet for a two-bedroom ADU, with detached ADUs up to 1,200 square feet allowed at the city discretion and the state 800 square foot by 16 foot height safe-harbor guaranteeing approval regardless of local rules. Junior ADUs are up to 500 square feet within an existing single-family dwelling footprint. Owner occupancy on the primary unit is required only for Junior ADUs, not for standard ADUs permitted after 2020. Setbacks are four feet side and rear for most detached ADUs. Parking is not required if the ADU is within one-half mile of public transit or in a historic district. Impact fees are waived for ADUs under 750 square feet. ADUs can be rented for 30 days or more; short-term rental of ADUs under 30 days is typically prohibited by state law.