ADU Rules: Berkeley vs Sunol
How do adu rules rules compare between Berkeley, CA and Sunol, CA?
Berkeley and Sunol have similar restriction levels.
Berkeley, CA
Alameda County
Berkeley regulates ADUs and JADUs under Berkeley Municipal Code Chapter 23.306. One ADU plus one JADU is allowed per single-family lot citywide (Hillside Overlay allows one ADU OR one JADU). New detached ADUs are limited to 16 feet in height, with a 4-foot minimum side and rear setback, and JADUs are capped at 500 sq ft within the existing dwelling.
View full Berkeley rules →Sunol, CA
Alameda County
Sunol is an unincorporated CDP in Alameda County governed by Alameda County Code Title 17 (Zoning), specifically the new Chapter 17.55 (Accessory Dwelling Unit and Junior Accessory Dwelling Unit Ordinance) adopted by Ordinance O-2024-XX in 2024. The County allows one ADU plus one JADU on single-family lots in all residential zones with no minimum lot size, consistent with California Government Code §65852.2.
View full Sunol rules →Key Facts Comparison
| Fact | Berkeley | Sunol |
|---|---|---|
| Code Section | BMC 23.306 (Development Standards 23.306.030) | - |
| Units Allowed | 1 ADU + 1 JADU per single-family lot | - |
| Side/Rear Setback | 4 ft (new construction) | - |
| JADU Max Size | 500 sq ft (within dwelling) | - |
| STR Use | Prohibited by deed restriction | - |
| Governing Code | - | Alameda Co. Code Ch. 17.55 |
| Adopted | - | Ord. O-2024-XX (2024) |
| Max Detached ADU | - | 1,200 sq ft |
| Min Lot Size | - | None |
| Septic/Well | - | Alameda Co. EH review required |
Highlighted rows indicate differences between cities.
Berkeley FAQ
How many ADUs can I build in Berkeley?
Under BMC 23.306, a single-family lot may have one ADU plus one JADU. In the Hillside Overlay, the limit is one ADU or one JADU (not both).
Do I need a public hearing for a Berkeley ADU?
No. State law requires ministerial review without a public hearing based on objective criteria, and BMC 23.306 implements that standard for Berkeley.
Can I rent my Berkeley ADU as a short-term rental?
No. A recorded deed restriction required by BMC 23.306 prohibits short-term rental use (under 14 days) of any ADU or JADU.
Sunol FAQ
Who regulates ADUs in Sunol?
Sunol is unincorporated, so the Alameda County Community Development Agency regulates ADUs under Alameda County Code Title 17, Chapter 17.55, adopted in 2024 to implement California Government Code §65852.2.
Is there a minimum lot size for a Sunol ADU?
No. Chapter 17.55 of the Alameda County Code (adopted 2024) eliminated the minimum lot size for ADUs in the unincorporated areas, consistent with state ADU law.
Do I need septic approval for a Sunol ADU?
Yes for parcels not on municipal sewer/water. Alameda County Environmental Health reviews septic-system capacity and well water before the building permit is issued.
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