Tiny Homes: Petaluma vs Sonoma
How do tiny homes rules compare between Petaluma, CA and Sonoma, CA?
Petaluma has fewer restrictions than Sonoma.
Petaluma, CA
Sonoma County
California HCD guidance and Health and Safety Code 18007 classify many tiny homes on wheels as manufactured housing or ADUs, granting statewide siting protections.
View full Petaluma rules →Sonoma, CA
Sonoma County
The City of Sonoma has not adopted the County's movable-tiny-home (THOW) program — within city limits a tiny home is only legal as a permanent-foundation ADU built to the California Building Code under SMC Chapter 19.45.
View full Sonoma rules →Key Facts Comparison
| Fact | Petaluma | Sonoma |
|---|---|---|
| Statute | Health & Safety Code 18007 | - |
| ADU pathway | Gov Code 65852.2 | - |
| Standards | HUD or ANSI 119.5 | - |
| Regulator | HCD | - |
| Tiny home on wheels (THOW) | - | Not permitted as a residence in city limits |
| Foundation-built tiny ADU | - | Allowed under SMC 19.45 (CBC compliant) |
| Minimum efficiency unit size | - | 150 sq ft (Cal. HSC §17958.1) |
| County TEM permit | - | Applies only in unincorporated Sonoma County, not the City |
| Required utilities | - | City sewer and water connection |
Highlighted rows indicate differences between cities.
Petaluma FAQ
Can I park a tiny home on wheels in my backyard full time?
Generally no, unless it qualifies as an ADU on a foundation or your city has a specific movable-tiny-house ordinance. RVs are limited to RV parks.
Are foundation-built tiny homes protected by ADU law?
Yes. A tiny home meeting ADU size and code requirements receives the full ministerial approval protections of Government Code 65852.2 statewide.
Sonoma FAQ
Can I live in a tiny home on wheels in the City of Sonoma?
No. The City has not adopted the County's Temporary Occupancy (TEM) tiny-home-on-wheels program from Ordinance No. 6406. Within City limits, a tiny home must be built to the California Residential Code, placed on a permanent foundation, and permitted as an ADU under SMC Chapter 19.45.
How small can a legal tiny ADU be?
California Health & Safety Code §17958.1 allows efficiency dwelling units down to 150 sq ft of habitable floor area, and SMC 19.45.040 sets the upper cap at 850 sq ft (studio/1BR) or 1,000 sq ft (2BR). The unit still has to meet CBC fire, egress, and energy requirements — important in Sonoma's WUI fire areas.
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