2010 California Code
Business and Professions Code
Chapter 16. Rental Vehicles

13800.  (a) Notwithstanding any other provision of this division, a
rental vehicle's fuel gauge installed by the vehicle's manufacturer
may be used in a rental transaction by a rental company to calculate
an optional charge for fueling when any of the following occurs:
   (1) The customer could have avoided incurring the charge by
returning the rental vehicle with the same amount of fuel as was in
the fuel tank at the commencement of the rental.
   (2) The customer chose to purchase the amount of fuel inside the
fuel tank at the commencement of the rental.
   (b) Nothing in this section shall be interpreted to preclude a
rental company from offering additional fueling options to customers
besides those described in subdivision (a).