San Bernardino County, CA Accessory Structures: Tiny Homes (2026)

San Bernardino County does not have a standalone tiny-home code. The pathway to a legal permanent tiny dwelling on a residential parcel is the accessory dwelling unit standards in Development Code Chapter 84.01. The County's ADU definition states that an accessory dwelling unit may include an efficiency unit, as defined in Section 17958.1 of the Health and Safety Code, and a manufactured home, as defined in Section 18007 of the Health and Safety Code. Under Section 84.01.060(e)(5), the minimum ADU size is determined by the current edition of the California Residential Code or as certified by the California Department of Housing and Community Development; the County's ADU Standards table lists a 150-200 square-foot minimum livable area. Because the unit must provide permanent provisions for living, sleeping, eating, cooking, and sanitation on a foundation, a tiny house on wheels (a recreational-vehicle-style movable structure) does not qualify as a permanent ADU. Recreational vehicles are only allowed as temporary labor quarters during limited harvest or seasonal periods with the required permits (Section 84.01.030(d)). A manufactured or modular tiny home meeting state building standards, placed on a permanent foundation and processed as an ADU, is the compliant route. Detached units are capped at 1,200 square feet with 18-foot height and 4-foot side/rear setbacks.