Cal. Water Code § 60340

If the board of a district shall have probable cause to believe that the production of ground water from any water-producing facility is in excess of that disclosed by the sworn statements covering such water-producing facility, or if no statements are filed covering a water-producing facility, the board of such district may cause an investigation and report to be made concerning the production of ground water from such water-producing facility. The board of the district may fix the amount of ground water production from any such water-producing facility at an amount not to exceed the maximum production capacity of such water-producing facility; provided, however, where a water-measuring device is permanently attached thereto, the record of production as disclosed by such water-measuring device shall be presumed to be accurate and the burden is upon the district to establish to the contrary. After such determination has been made by the board of the district, a written notice thereof shall be mailed to the operator of such water-producing facility at his address as shown by the district’s records. Any such determination made by the district shall be conclusive on the operator, and on any producer producing water from such water-producing facility, and the replenishment assessment based thereon, together with interest and penalties, shall be payable forthwith, unless such operator or producer shall file with the board of directors of the district within ten (10) days after the mailing of such notice a written protest setting forth the ground or grounds for protesting the amount of production so fixed or the replenishment assessment, interest, and penalties so levied thereon. Upon the filing of such protest, said board shall hold a hearing at which time the total amount of the ground water production and the replenishment assessment thereon shall be determined, and the interest and penalties fixed, which action shall be conclusive if based upon substantial evidence. A notice of such hearing shall be mailed to protestant at least 10 days before the date fixed for the hearing. Notice of the determination by the board shall be mailed to each protestant. The producer shall have 20 days from the date of mailing of such notice to pay the replenishment assessment, interest and penalties so fixed by the board.