Santa Rosa, CA Accessory Structures: Tiny Homes (2026)

220 lets a Tiny Home on Wheels sit on a residential parcel as an accessory habitable structure to a single-family dwelling, but only one per parcel and only where a single-family home already exists or is under an active building permit. The unit needs its own City building permit, must be licensed and registered with the California DMV, and must carry a label certifying compliance with Cal. 5 or NFPA 1192 third-party certification. Size is capped at 400 square feet exterior wall to exterior wall, with a 150-square-foot minimum first floor, 6-foot-8-inch minimum ceiling height, and a 14-foot maximum height from the bottom of the wheels to the roof.

Setbacks run 20 feet from the front property line, 5 feet from the side, 10 feet on a side-corner, and 5 feet from the rear, with additional setbacks layered on in the Scenic Road, Historic, or Gateway combining districts. A Tiny Home on Wheels cannot go on a parcel that already has a detached ADU, cannot sit closer to the street than the main house except on corner lots with review-authority approval, and is barred outright on slopes of 10 percent or greater. It has to sit on a paved surface sufficient to bear its weight, keep its wheels attached, stay towable rather than self-propelled, provide smoke detectors in every sleeping area, and connect to water, wastewater, and electrical service under applicable Building Code standards.