ADU Rules: Altadena vs South Gate
How do adu rules rules compare between Altadena, CA and South Gate, CA?
South Gate has fewer restrictions than Altadena.
Altadena, CA
Los Angeles County
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.
View full Altadena rules →South Gate, CA
Los Angeles County
South Gate must allow accessory dwelling units (ADUs) and junior ADUs (JADUs) on any parcel with an existing or proposed single-family or multifamily dwelling, in conformance with Cal. Gov. Code §65852.2 and §65852.22. The South Gate Municipal Code Title 11 (Zoning) implements these state ADU standards ministerially.
View full South Gate rules →Key Facts Comparison
| Fact | Altadena | South Gate |
|---|---|---|
| Governing Code | LA County Code §22.140.640 | - |
| Single-Family | 1 ADU + 1 JADU per lot | - |
| Multifamily Detached | Up to 2 new (20 ft max) | - |
| WUI Fire Zone | Chapter 7A applies (hillside) | - |
| Side/Rear Setback | 4 ft (new construction) | - |
| Governing law | - | Cal. Gov. Code §65852.2 (ADUs); §65852.22 (JADUs) |
| Local code | - | South Gate Municipal Code Title 11 (Zoning), Ch. 11.25 |
| By-right ADU size | - | 800 sq ft, 16-ft height, 4-ft setbacks |
| Max detached ADU | - | 1,200 sq ft (state floor) |
| JADU max | - | 500 sq ft (within existing SFD) |
| Review type | - | Ministerial (no public hearing) |
| Approval timeline | - | 60 days from complete application (Gov. Code §65852.2(b)) |
Highlighted rows indicate differences between cities.
Altadena FAQ
Who regulates ADUs in Altadena?
Altadena is unincorporated, so LA County Regional Planning regulates ADUs under LA County Code Title 22 §22.140.640, not a separate city ordinance.
Do hillside or fire rules apply to Altadena ADUs?
Yes. Altadena's hillside neighborhoods are in LA County's Very High Fire Hazard Severity Zone, requiring Chapter 7A ignition-resistant construction and Fire Code §325 brush clearance. Hillside-grading provisions of Title 22 apply on slopes steeper than 10%.
How big can my Altadena ADU be?
Under §22.140.640, a detached ADU on a single-family lot may be up to 1,200 sq ft; multifamily-lot ADUs have no maximum size cap. JADUs are capped at 500 sq ft.
South Gate FAQ
Can South Gate ban ADUs in single-family zones?
No. Cal. Gov. Code §65852.2 preempts local bans. South Gate must allow ADUs ministerially on any single-family or multifamily lot.
Do I need a public hearing for an ADU in South Gate?
No. State law requires ministerial (over-the-counter) approval within 60 days of a complete application — no Planning Commission hearing.
Can I build an ADU and a JADU on the same lot?
Yes. State law allows one ADU plus one JADU on a single-family lot in South Gate.
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