California Code, Revenue and Taxation Code - RTC § 8752

(a) Except as provided in subdivision (b), on or before the last day of the calendar month following each quarterly period, every user shall, except as otherwise provided in Section 8608, file with the board a return in the form as prescribed by the board, which may include, but not be limited to, electronic media showing the amount of any tax due and any other information as the board may require to carry out the purposes of this part.Returns shall be authenticated in a form or pursuant to methods as may be prescribed by the board.

(b) This section shall not be applicable to any user whose sole use of fuel subject to the tax imposed by this part is for the propulsion of a privately operated passenger automobile, provided that the fuel used in this state, except fuel brought into this state in the fuel tank of the vehicle, is purchased from and delivered into the fuel tank of the vehicle by a vendor holding a permit issued under this part.