Riverside, CA Accessory Structures: Tiny Homes (2026)

Riverside is one of the relatively few California cities with a written movable ADU (MADU) ordinance. Under RMC Chapter 19.442, a MADU is a self-contained, permitted dwelling unit between 150 and 430 square feet measured within the exterior walls, placed on a single-family lot in addition to (or together with) any standard ADU. The MADU must connect to permanent water, sewer, and electrical service and meet California Residential Code habitability standards (min. 70 sq ft sleeping room, 7-foot ceilings, egress, smoke/CO alarms). A standard detached ADU in Riverside may be up to 1,200 sq ft (attached ADUs are capped at 50% of the existing dwelling living area or 1,200 sq ft, whichever is less, with a floor of 850 sq ft for studios/1-BR and 1,000 sq ft for 2+ BR per Gov. Code §65852.2). JADUs are capped at 500 sq ft. Tiny homes on wheels (THOWs) are classified as recreational vehicles under Cal. Health & Safety Code §18010 and California Vehicle Code §362 and cannot be used as a permanent residence on a single-family lot; they may only be parked as RVs in licensed RV parks or mobilehome parks zoned for that use under RMC Title 19.