Rancho Cucamonga, CA Accessory Structures: Tiny Homes (2026)

Tiny home regulation in Rancho Cucamonga depends on whether the unit is on a permanent foundation or on wheels. A tiny home on a permanent foundation under 1,200 square feet can qualify as an Accessory Dwelling Unit (ADU) under California Government Code 65852.2, or under 500 square feet as a Junior ADU under 65852.22, provided it meets the California Residential Code (insulation, egress, plumbing, electrical, permanent heat source, minimum ceiling height of 7 feet, and a bathroom and kitchen). Tiny homes on wheels (THOWs) that meet American National Standards Institute (ANSI) 119.5 Park Model RV standards or HUDs manufactured housing code may be permitted on private residential property only as temporary structures, not permanent dwellings, and typically only as a caregiver dwelling under very narrow exceptions (SB 1076 movable tiny home rules, still limited locally). THOWs on a trailer are defined as recreational vehicles and cannot be used as a permanent residence inside Rancho Cucamonga city limits. RV parks and mobile home parks are separately regulated and generally do not allow THOWs. AB 2533 and SB 9 have expanded options but Rancho Cucamongas implementation remains focused on site-built ADUs. Tiny homes in the foothill VHFHSZ must meet Chapter 7A ignition-resistant construction and 100-foot defensible space.