Garage Conversions: Berkeley vs Sunol
How do garage conversions rules compare between Berkeley, CA and Sunol, CA?
Berkeley and Sunol have similar restriction levels.
Berkeley, CA
Alameda County
Berkeley allows garage-to-ADU and garage-to-JADU conversions under BMC 23.306, consistent with California Government Code §65852.2. No replacement parking is required when a garage is converted to an ADU, and the existing garage's setbacks are preserved for the converted footprint.
View full Berkeley rules →Sunol, CA
Alameda County
Garage conversions to ADUs in unincorporated Sunol are governed by Alameda County Code Title 17, Chapter 17.55 (adopted 2024) and California Government Code §65852.2. No replacement parking is required when a garage is converted, and the existing garage's setbacks are preserved. Most Sunol parcels are on septic systems requiring Alameda County Environmental Health review.
View full Sunol rules →Key Facts Comparison
| Fact | Berkeley | Sunol |
|---|---|---|
| Code Section | BMC 23.306; CA Gov Code §65852.2 | - |
| Replacement Parking | Not required | Not required |
| Existing Setbacks | Preserved for conversion footprint | Preserved for conversion |
| Conversion Expansion | Up to 150 sq ft for ingress/egress | - |
| Permit Required | Yes — building permit | - |
| Governing Code | - | Alameda Co. Code §17.55 |
| JADU Cap | - | 500 sq ft (within primary) |
| Septic Review | - | Alameda Co. EH required |
Highlighted rows indicate differences between cities.
Berkeley FAQ
Do I have to replace parking if I convert my Berkeley garage to an ADU?
No. Under BMC 23.306 and state law, Berkeley cannot require replacement parking when an existing garage is converted to an ADU or JADU.
Can I add square footage to my garage during a conversion?
Yes — BMC 23.306 allows a physical addition of up to 150 sq ft to accommodate ingress, egress, and code-required features during a conversion.
Are fire sprinklers required for my converted garage ADU?
Only if the primary residence has them, per state ADU law. Berkeley follows the §65852.2 rule that ADUs cannot be required to install sprinklers if the primary home is not required to have them.
Sunol FAQ
Do I need to replace parking if I convert my Sunol garage to an ADU?
No. Cal. Gov Code §65852.2 and Alameda County Code §17.55 prohibit the County from requiring replacement parking when an existing garage is converted to an ADU.
Are existing garage setbacks grandfathered for a Sunol conversion?
Yes. Under state ADU law as implemented by Alameda County Code §17.55, the existing footprint and setbacks of the garage are preserved for the conversion. Only added square footage must meet the 4-foot new-construction setback.
Do I need septic approval for my Sunol garage-conversion ADU?
Yes for parcels on septic systems. Alameda County Environmental Health reviews septic capacity for the added bedroom load before the building permit is issued.
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