Garage Conversions: Petaluma vs Sonoma
How do garage conversions rules compare between Petaluma, CA and Sonoma, CA?
Petaluma and Sonoma have similar restriction levels.
Petaluma, CA
Sonoma County
Under California Gov Code §65852.2(e), Petaluma must approve conversion of an existing garage to an ADU and may not require replacement parking even if the conversion eliminates required parking.
View full Petaluma rules →Sonoma, CA
Sonoma County
The City permits converting an existing garage into an ADU under SMC 19.45.040 with no replacement parking required; state law (Gov. Code §66323) and the City waive parking when the ADU is within ½ mile of transit or in the historic district.
View full Sonoma rules →Key Facts Comparison
| Fact | Petaluma | Sonoma |
|---|---|---|
| Replacement Parking | Not required (state law) | - |
| Approval | Ministerial, ≤60 days | - |
| Code | Petaluma IZO §7.030 | - |
| Replacement parking when garage becomes ADU | - | Not required (SMC 19.45.040 / Gov. Code §66314) |
| ADU parking requirement | - | Waived for conversions of existing structures, ½ mi of transit, or historic district |
| Setback for converted garage ADU | - | Keeps existing legal setbacks; new construction needs 4 ft side/rear |
| Max size | - | 850 sq ft (studio/1BR), 1,000 sq ft (2BR) |
| Utility connection | - | No new separate connection required on single-family lots |
Highlighted rows indicate differences between cities.
Petaluma FAQ
Can I convert just part of the garage?
Yes — partial conversions are allowed but the remaining garage must still meet code.
Sonoma FAQ
Do I have to add new driveway parking if I convert my garage to an ADU?
No. SMC 19.45.040 conforms to Gov. Code §66314 — no replacement parking is required for the primary dwelling when its garage is converted to an ADU, and the new ADU itself is also exempt from parking when it is a conversion of an existing structure.
How big can my garage-conversion ADU be in Sonoma?
Up to 850 sq ft for a studio or one-bedroom and up to 1,000 sq ft for two bedrooms, capped at two bedrooms (SMC 19.45.040). If the garage is larger, the unit is still limited to these floor areas.
Compare other topics
See how Petaluma and Sonoma 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