ADU Rules: Pasadena vs Topanga
How do adu rules rules compare between Pasadena, CA and Topanga, CA?
Pasadena and Topanga have similar restriction levels.
Pasadena, CA
Los Angeles County
Pasadena allows ADUs under California state law (AB 68, SB 13, AB 881). Both attached and detached ADUs are permitted. The city has streamlined its permitting process to comply with state mandates.
View full Pasadena 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 | Pasadena | Topanga |
|---|---|---|
| Detached ADU | Up to 1,200 sq ft | - |
| Junior ADU | Up to 500 sq ft | - |
| Setback | 4 feet for detached ADU | - |
| Parking | None required near transit | - |
| 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) |
| Side/Rear Setback | - | 4 ft (new construction) |
Highlighted rows indicate differences between cities.
Pasadena FAQ
Can I build an ADU in Pasadena?
Yes. California law requires cities to allow ADUs. Detached units up to 1,200 sq ft and junior ADUs up to 500 sq ft are permitted.
Do I need to live on the property?
No. California state law removed owner occupancy requirements for ADUs.
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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