Accessory Structures in Antioch, CA (2026)
5 verified accessory structures rules for Antioch, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Antioch implements California state ADU law through Antioch Municipal Code Section 9-5.3805, allowing one ADU plus one JADU on single-family lots with a four-foot side and rear setback, a 16-foot height limit for detached ADUs, and ministerial 60-day approval.
Antioch ADU and JADU Rules (AMC 9-5.3805)
Few RestrictionsAntioch Municipal Code § 9-5.3805 (Accessory Dwelling Units)
An Accessory Dwelling Unit (ADU) means an attached or detached residential dwelling unit that provides complete independent living facilities for one or more persons and is either located on a lot with a proposed or existing primary residence, or located in the IH Overlay District. The minimum required setback for a new construction ADU on a single-family property is 4 feet from the rear and in...
Shed Rules
Antioch Municipal Code Section 9-5.603 caps accessory structures in residential districts at 15 feet tall, requires a five-foot rear and interior side setback, and exempts truly portable storage sheds (under 120 sq ft, under 8 ft tall, no foundation) from permit requirements.
Antioch Shed and Accessory Building Rules (AMC 9-5.603)
Some RestrictionsAntioch Municipal Code § 9-5.603 (Accessory Buildings)
In residential districts, the maximum allowable height is 15 feet for accessory structures. Detached accessory structures shall be located behind the required front yard setback and cover no more than 40% of the rear yard area required for the main building. The minimum side yard for accessory structures is 20 feet on corner lots and five feet on interior lots. A five-foot rear yard setback is ...
Garage Conversions
Antioch follows California state law allowing ministerial, by-right conversion of an existing garage into an ADU, with no setback added beyond fire-safety distance, no replacement parking required, and no fire-sprinkler requirement unless the primary dwelling already has sprinklers.
Antioch Garage-to-ADU Conversion Rules
Few RestrictionsCalifornia Government Code § 65852.2(a)(1)(D)(xi) and § 65852.2(b)(1)
(b)(1) When a local agency receives its first application on or after July 1, 2003, for a permit pursuant to this subdivision, the application shall be considered ministerially without discretionary review or a hearing... (a)(1)(D)(xi) When a garage, carport, or covered parking structure is demolished in conjunction with the construction of an accessory dwelling unit or converted to an accessor...
Carport Rules
Carports in Antioch are governed by the Zoning Code as accessory structures. Detached carports must sit behind the front yard setback, must be at least 5 feet from interior side and rear lot lines (20 feet from a side street on a corner lot), and may not exceed 15 feet in height. The garage or carport opening serving a residence must be at least 20 feet from the exterior property line so a parked car will not overhang the sidewalk.
accessory-structures/carport-rules
Some RestrictionsTiny Homes
Antioch regulates tiny homes through its ADU ordinance at Antioch Municipal Code 9-5.3805, which expressly recognizes manufactured homes (Cal. Health & Safety Code 18007) and efficiency units (Cal. Health & Safety Code 17958.1) as Accessory Dwelling Units. A detached tiny-home ADU is permitted up to 1,200 square feet at 16 feet in height with 4-foot side and rear setbacks. Tiny homes on wheels (THOWs), park-model RVs, and recreational vehicles are not recognized as ADUs and may not be used as permanent dwellings outside a permitted park.
accessory-structures/tiny-homes
Some RestrictionsLooking for Contra Costa County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Antioch city rules.
Accessory Structures in Contra Costa County →