ADU Rules: Petaluma vs Santa Rosa
How do adu rules rules compare between Petaluma, CA and Santa Rosa, CA?
Petaluma has fewer restrictions than Santa Rosa.
Petaluma, CA
Sonoma County
Petaluma IZO §7.030 implements California's permissive ADU laws (Gov Code §65852.2). Most single-family lots may build at least one ADU and one Junior ADU.
View full Petaluma rules →Santa Rosa, CA
Sonoma County
Santa Rosa allows one ADU plus one JADU on single-family lots under Zoning Code Section 20-42.130, adopted by urgency Ordinance on March 3, 2020 to align with California Government Code Sections 65852.2 and 65852.22. Detached ADUs are capped at 1,200 sq ft with 4-ft side/rear setbacks and a 16-ft (one-story) or 27-ft (two-story) height limit; JADUs are capped at 500 sq ft and must sit entirely within the existing single-family dwelling walls.
View full Santa Rosa rules →Key Facts Comparison
| Fact | Petaluma | Santa Rosa |
|---|---|---|
| Detached ADU Max | 800 sq ft (statewide standard) | - |
| Setback | 4 ft side/rear | - |
| Approval Window | 60 days | - |
| Max detached ADU size | - | 1,200 sq ft habitable space |
| Max JADU size | - | 500 sq ft (+150 sq ft allowed for separate entrance) |
| Side/rear setback (one-story) | - | 4 ft minimum |
| Side/rear setback (two-story) | - | 8 ft minimum |
| Height limit (one-story) | - | 16 ft |
| Height limit (two-story) | - | 27 ft |
| Parking required | - | 1 space (multiple exemptions) |
| Owner occupancy (ADU) | - | Not required |
| Owner occupancy (JADU) | - | Required by recorded deed restriction |
| Permit approval | - | Ministerial, 60-day decision deadline |
| Short-term rentals | - | Prohibited (<30-day terms not allowed) |
| Number per single-family lot | - | 1 ADU + 1 JADU |
Highlighted rows indicate differences between cities.
Petaluma FAQ
Do I need to live in the main house?
Owner-occupancy requirements have been suspended statewide through Jan 1, 2025 (now extended).
Santa Rosa FAQ
Do I need owner-occupancy to build an ADU in Santa Rosa?
Not for an ADU; the 2020 ordinance removed owner-occupancy in compliance with state law. JADUs do require owner-occupancy via a deed restriction recorded with Sonoma County per Subsection G.2 of Section 20-42.130.
Can I rent my Santa Rosa ADU short-term?
No. Subsection B.4 of Section 20-42.130 states ADUs 'shall not be used for rentals with terms of less than 30 days.' The same restriction applies to JADUs per Subsection F.1.c.
How tall can a two-story ADU be?
27 feet maximum per Subsection E.4.a. When an ADU is located above an existing or proposed garage, the entire combined structure cannot exceed 27 feet.
Do I need to add parking when converting my garage to an ADU?
No. Subsection E.10.h provides that no replacement off-street parking spaces are required when an ADU is created through the conversion or demolition of a garage, carport, or covered parking structure.
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