Accessory Structures in Altadena, CA (2026)
4 verified accessory structures rules for Altadena, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Altadena is an unincorporated CDP in Los Angeles County governed by LA County Code Title 22 §22.140.640 (Accessory Dwelling Units and Junior Accessory Dwelling Units), most recently amended April 2024. Single-family lots may add one ADU plus one JADU; multifamily lots may add up to two detached new-construction ADUs plus conversion ADUs in non-livable existing space.
Altadena ADU Rules (LA County Title 22)
Some RestrictionsShed Rules
Sheds 120 sq ft or smaller and ≤12 ft tall typically don't need a building permit in Altadena, but they still must comply with Altadena CSD setbacks. Anything larger needs a permit.
Altadena Shed Rules (LA County Code 22.110.040 + CBC)
Few RestrictionsGarage Conversions
Garage conversions to ADUs in unincorporated Altadena are governed by LA County Code Title 22 §22.140.640 and California Government Code §65852.2. No replacement parking is required when an existing garage is converted, and existing setbacks are grandfathered. Properties in Very High Fire Hazard Severity Zones also trigger Chapter 7A wildland-urban interface standards.
Altadena Garage Conversion to ADU (LA County)
Some RestrictionsCarport Rules
Carports in Altadena are accessory structures regulated under Altadena CSD 22.306.070 and LA County Code 22.110.040. They count toward the lot-coverage formula and the 2-space minimum parking requirement.
Altadena Carport Rules (Altadena CSD + LA County Code 22.110)
Some RestrictionsLooking for Los Angeles County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Altadena city rules.
Accessory Structures in Los Angeles County →