Wat. Code, § 10731

(a) Following an investigation pursuant to Section 10725.4, the governing body may make a determination fixing the amount of groundwater production from the groundwater extraction facility at an amount not to exceed the maximum production capacity of the facility for purposes of levying a groundwater charge. If a water-measuring device is permanently attached to the groundwater extraction facility, the record of production as disclosed by the water-measuring device shall be presumed to be accurate unless the contrary is established by the groundwater sustainability agency after investigation.

(b) After the governing body makes a determination fixing the amount of groundwater production pursuant to subdivision (a), a written notice of the determination shall be mailed to the owner or operator of the groundwater extraction facility at the address as shown by the groundwater sustainability agency’s records. A determination made by the governing body shall be conclusive on the owner or operator and the groundwater charges, based on the determination together with any interest and penalties, shall be payable immediately unless within 20 days after the mailing of the notice the owner or operator files with the governing body a written protest setting forth the ground for protesting the amount of production or the groundwater charges, interest, and penalties. If a protest is filed pursuant to this subdivision, the governing body shall hold a hearing to determine the total amount of the groundwater production and the groundwater charges, interest, and penalties. Notice of the hearing shall be mailed to each protestant at least 20 days before the date fixed for the hearing. Notice of the determination of the governing body hearing shall be mailed to each protestant. The owner or operator shall have 20 days from the date of mailing of the determination to pay the groundwater charges, interest, and penalties determined by the governing body.