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

There is no dedicated tiny-home ordinance in unincorporated San Diego County. A movable tiny home built on a permanent foundation is treated as an Accessory Dwelling Unit under Section 6156 of the Zoning Ordinance and California ADU law (Gov. Code 66310-66342), meaning it must satisfy ADU standards: a detached unit may not exceed 1,200 sq ft, must observe a minimum 4-foot side and rear setback, is limited to 25 feet in height, and must meet building and fire standards for dwelling units. A 'tiny home on wheels' is generally classified as a trailer coach or recreational vehicle. Under Zoning Ordinance Section 6940, the use of a trailer coach outside a mobilehome park is permitted only for specific purposes (such as security personnel quarters, dwellings on a private lot established under Section 6502, or housing established under the Accessory Use Regulations), and Section 6118 allows temporary trailer-coach uses only for limited purposes such as a construction or political campaign office. Recreational-vehicle occupancy in a recreational vehicle park is also time-limited under Section 6456: a person in a vehicle with full hook-ups may not occupy a space more than 90 days in any 12-month period (30 days for tents or vehicles without full hook-ups). A tiny home on wheels therefore cannot ordinarily serve as a permanent residence on a standard residential lot.