ADU Rules: El Monte vs Topanga
How do adu rules rules compare between El Monte, CA and Topanga, CA?
El Monte and Topanga have similar restriction levels.
El Monte, CA
Los Angeles County
El Monte Municipal Code Chapter 17.110 regulates Accessory Dwelling Units (ADUs) and Junior ADUs per California Government Code Sections 66314-66339. Detached ADUs may be up to 1,200 sq ft; attached up to 800 sq ft or 50% of the primary dwelling.
View full El Monte 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 | El Monte | Topanga |
|---|---|---|
| Code Section | EMMC Ch. 17.110 | - |
| Detached Max | 1,200 sq ft | - |
| Attached Max | 800 sq ft or 50% of primary | - |
| Max Per Lot | 2 ADUs + 1 JADU | - |
| STR Use | Prohibited | - |
| Building & Safety | (626) 580-2037 | - |
| 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.
El Monte FAQ
How big can an ADU be in El Monte?
Detached ADUs may be up to 1,200 sq ft. Attached ADUs up to 800 sq ft or 50% of the primary dwelling. Up to 2 ADUs and 1 JADU per single-family lot.
Can I convert my El Monte garage to an ADU?
Yes. Garage conversions to ADUs are permitted under California state law and El Monte's Chapter 17.110. A building permit is required.
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).
Compare other topics
See how El Monte and Topanga compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool