Tiny Homes: Fontana vs Ontario
How do tiny homes rules compare between Fontana, CA and Ontario, CA?
Fontana has fewer restrictions than Ontario.
Fontana, CA
San Bernardino County
Stationary tiny homes in Fontana permit as ADUs under Gov Code 65852.2 up to 1,200 sq ft. Tiny houses on wheels are treated as RVs and cannot be permanent residences outside an RV park.
View full Fontana rules →Ontario, CA
San Bernardino County
Foundation-built tiny homes qualify as ADUs under Gov Code 65852.2 in Ontario. Tiny homes on wheels are treated as RVs or park trailers and cannot be used as permanent dwellings on residential lots.
View full Ontario rules →Key Facts Comparison
| Fact | Fontana | Ontario |
|---|---|---|
| Stationary tiny homes | Permitted as ADUs up to 1,200 sq ft under GC 65852.2 | - |
| HUD-code tiny homes | Allowed on permanent foundation with tie-down | - |
| Tiny homes on wheels | Treated as RVs - no permanent residential use outside RV park | - |
| Plan check required | Title 24, CRC, and structural engineering for ADU tiny homes | - |
| Approval timeline | 60 days ministerial for compliant ADU tiny home | - |
| Foundation tiny home | - | Legal as ADU under Gov 65852.2 |
| THOW (wheels) | - | Treated as RV or park trailer |
| Permanent THOW living | - | Not allowed on residential lot |
| ADU size cap | - | Up to ~1,200 sq ft per state |
| Permit | - | Ontario Building and Safety |
Highlighted rows indicate differences between cities.
Fontana FAQ
Can I put a tiny home in my Fontana backyard?
Yes if it is built to code on a permanent foundation and permitted as an ADU. A tiny house on wheels used as a permanent residence is not allowed.
Is a Park Model RV legal to live in on my Fontana property?
No. California treats park-model RVs as recreational vehicles, and Fontana prohibits using an RV as a full-time residence on private residential property.
What size tiny home can I permit as an ADU?
Detached ADUs up to 1,200 square feet are allowed under state law, with minimum 4-foot side and rear setbacks and CRC structural compliance.
Ontario FAQ
Can I live full time in a tiny home on wheels parked at my Ontario house?
No. A tiny home on wheels is classified as an RV, and using it as a permanent residence on a single-family lot violates the RV occupancy rules and zoning.
Can I build a foundation-based tiny home as an ADU?
Yes. A site-built tiny home on a permanent foundation is a legal ADU under Government Code 65852.2 and must be ministerially approved if it meets state ADU standards.
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