Accessory Structures in Brentwood, CA (2026)
3 verified accessory structures rules for Brentwood, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Brentwood must allow Accessory Dwelling Units on any single-family lot under California Government Code Section 65852.2, as expanded by AB 68, AB 881, and SB 13. Detached ADUs up to 800 sq ft with 4-foot setbacks are ministerial approvals processed within 60 days. AB 1033 now allows selling an ADU separately from the primary home.
Accessory Structures: Adu Permits
Few RestrictionsShed Rules
Brentwood follows the California Building Code exemption allowing detached accessory structures under 120 square feet to be built without a building permit. Sheds must still comply with zoning setbacks, height limits, and HOA rules. Structures over 120 sq ft or with utilities require a building permit and Community Development review.
Accessory Structures: Sheds
Few RestrictionsGarage Conversions
Brentwood garages must meet California Residential Code requirements for fire separation, including 5/8-inch Type X drywall on walls and ceilings separating the garage from living space and a self-closing, self-latching 20-minute fire-rated door. Conversion to an ADU is permitted by right under AB 68, and the city cannot require replacement parking for transit-adjacent conversions.
Accessory Structures: Garage Rules
Some RestrictionsLooking for Contra Costa County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Brentwood city rules.
Accessory Structures in Contra Costa County →