California Code, Revenue and Taxation Code - RTC § 8607

“Use” includes the placing of fuel into any receptacle on a motor vehicle from which fuel is supplied for the propulsion of the vehicle unless the operator of the vehicle establishes to the satisfaction of the board that the fuel was consumed for a purpose other than the operation of a motor vehicle within this State and, with respect to fuel brought into this State in any such receptacle, the consumption of the fuel in this State. A person placing fuel in a receptacle on a motor vehicle of another who holds a valid use fuel tax permit is not deemed to have used the fuel.