Tiny Homes: Ontario vs Rialto
How do tiny homes rules compare between Ontario, CA and Rialto, CA?
Rialto has fewer restrictions than Ontario.
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 →Rialto, CA
San Bernardino County
Tiny homes in Rialto are regulated either as ADUs under California Government Code §65852.2 (state ADU law) and Rialto Municipal Code Title 18, or as RVs/manufactured housing under state HCD rules. Permanent tiny homes on foundations qualify as ADUs and benefit from California's ministerial-approval preemption.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| 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 | - |
| Permanent tiny home | - | Processed as ADU per Cal. Gov. Code §65852.2 |
| On wheels (THOW) | - | RV under HCD Title 25 / Vehicle Code - not a dwelling unless ADU-certified |
| Building code | - | CRC Appendix Q for tiny houses under 400 sf |
| Local zoning | - | RMC Title 18 (must conform to state ADU law) |
Highlighted rows indicate differences between cities.
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.
Rialto FAQ
Can I live in a tiny home in my Rialto backyard?
Yes if it is permitted as an ADU under Cal. Gov. Code §65852.2 and built to the California Residential Code (CRC Appendix Q applies to tiny houses under 400 sf). Living in an RV or trailer as a permanent residence outside an RV park is prohibited.
Can Rialto require owner-occupancy for an ADU tiny home?
State ADU law currently bars Rialto from imposing owner-occupancy requirements on most newly permitted ADUs; check current Gov. Code §65852.2 amendments for the applicable date range.
Compare other topics
See how Ontario and Rialto 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