Riverside, CA Accessory Structures: Tiny Homes (2026)

Riverside has two distinct tiny-home categories. First, a tiny home on a permanent foundation built to the California Residential Code can be permitted as an ADU. The CRC requires a minimum habitable floor area of 70 square feet in a sleeping room and a minimum horizontal dimension of 7 feet, with most tiny ADUs ranging from 150 to 500 square feet. State law requires ministerial approval of ADUs up to 850 sq ft (1,200 sq ft for a two-bedroom detached ADU), so a 300-square-foot tiny home built to code fits squarely in that process and receives the standard 4-foot setback and 16-foot height limits. Second, a tiny home on wheels (THOW) built on a trailer chassis is classified as either a recreational vehicle (if certified to NFPA 1192 or ANSI A119.5) or a park model RV (ANSI A119.5). California and Riverside do not allow RVs to be used as permanent dwellings on single-family residential lots — RVs can be parked on private property for storage but cannot be hooked to utilities and occupied full-time as a residence. AB 1410 (2022) allows homeowners to use movable tiny houses as temporary housing during a declared emergency. Certified manufactured homes (HUD code) are permitted as primary dwellings in residential zones per state preemption and can also be permitted as ADUs. Permits, Title 24 energy compliance, and utility connections follow standard ADU requirements. Composting toilets and graywater setups are evaluated case-by-case. Long-term RV living is restricted to licensed RV parks and mobilehome parks zoned for that use.