Cal. Rev. & Tax. Code § 11108

A person shall, for the purposes provided in this part, be presumed to be operating a vehicle on the public highways only in the county of residence as it is reflected in the registration records of the Department of Motor Vehicles and he shall be subject to a vehicle license fee under this part only in that county. The department is authorized to establish administrative procedures for the collection of vehicle license fees. In determining the place of residence of a person the department shall be entitled to rely upon the address reflected in its records unless any such person or persons or county or district shall establish to the satisfaction of the department that the place of residence is elsewhere.