ADU Rules: Altadena vs Glendale
How do adu rules rules compare between Altadena, CA and Glendale, CA?
Glendale 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 →Glendale, CA
Los Angeles County
Glendale regulates ADUs and JADUs under Glendale Municipal Code (GMC) §30.34.080, with the most recent ordinance amendment adopted by City Council on December 3, 2024 to address California HCD compliance concerns. ADUs and JADUs are reviewed ministerially without a public hearing, consistent with California Government Code §65852.2.
View full Glendale rules →Key Facts Comparison
| Fact | Altadena | Glendale |
|---|---|---|
| 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) | 4 ft (new construction) |
| Code Section | - | GMC §30.34.080 |
| Detached Height | - | 16 ft (18 ft near transit) |
| Attached Height | - | 25 ft, max 2 stories |
| Multifamily Detached New | - | Up to 2 per lot |
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.
Glendale FAQ
How many ADUs can I build on a Glendale multifamily lot?
GMC §30.34.080 implements state law allowing conversion ADUs within non-livable existing multifamily space (up to 25% of existing units) plus up to two detached new-construction ADUs per lot.
How tall can my Glendale detached ADU be?
Detached ADUs are limited to 16 feet under GMC §30.34.080, or up to 18 feet (plus 2 feet for a matching roof pitch) if the property is within a half-mile of a major transit stop or high-quality transit corridor.
Do I need a public hearing for a Glendale ADU?
No. GMC §30.34.080 requires ministerial review without a public hearing, consistent with California Government Code §65852.2.
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