ADU Rules: South San Gabriel vs Topanga
How do adu rules rules compare between South San Gabriel, CA and Topanga, CA?
South San Gabriel and Topanga have similar restriction levels.
South San Gabriel, CA
Los Angeles County
LA County's ADU Ordinance (amended October 2024) allows accessory dwelling units in all residential zones of unincorporated areas. Applications go through EPIC-LA and are reviewed by the Department of Regional Planning. Pre-approved plans are available.
View full South San Gabriel rules →Topanga, CA
Los Angeles County
Topanga 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. Detached ADUs are capped at 1,200 sq ft; multifamily-lot ADUs have no maximum size under county rules. Topanga lies within the Santa Monica Mountains Coastal Zone, so a Coastal Development Permit also applies.
View full Topanga rules →Key Facts Comparison
| Fact | South San Gabriel | Topanga |
|---|---|---|
| Max ADU Size | 1,200 sq ft | - |
| JADU Max | 500 sq ft | - |
| Side/Rear Setback | 4 feet | 4 ft (new construction) |
| Max Height | 16 feet | - |
| Application | EPIC-LA portal | - |
| Governing Code | - | LA County Code §22.140.640 |
| Single-Family | - | 1 ADU + 1 JADU per lot |
| Multifamily Detached | - | Up to 2 new + conversion ADUs |
| Coastal Permit | - | Required (Santa Monica Mtns LCP) |
Highlighted rows indicate differences between cities.
South San Gabriel FAQ
Can I build an ADU in unincorporated LA County?
Yes. One ADU and one JADU are allowed per lot in all residential zones. Detached ADUs can be up to 1,200 square feet. Apply through the EPIC-LA portal.
Do I need to live on-site to have an ADU in LA County?
No. California state law eliminates owner-occupancy requirements for ADUs. You can rent both the main home and the ADU.
Topanga FAQ
Who regulates ADUs in Topanga?
Topanga is unincorporated, so LA County Department of Regional Planning regulates ADUs under LA County Code Title 22 §22.140.640, not a separate city ordinance.
Do I need a Coastal Development Permit for a Topanga ADU?
Yes. Topanga falls within the certified Santa Monica Mountains Local Coastal Program, so most ADU construction requires a Coastal Development Permit in addition to the building permit.
Can a Topanga multifamily lot add detached ADUs?
Yes. Under LA County Code §22.140.640, multifamily lots may add up to two detached new-construction ADUs plus conversion ADUs within non-livable space (up to 25% of existing units).
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