Cal. WAT § 31144.79

(a) If the district has probable cause to believe that the production of water from any water-producing facility is in excess of that disclosed by the sworn statements covering the water-producing facility, or if no statements are filed covering any water-producing facility, the district may cause an investigation and report to be made concerning the production of water from each such water-producing facility. The district may fix the amount of water production from any such water-producing facility at an amount not to exceed the maximum production capacity of the water-producing facility.

(b) After the determination has been made by the district, a written notice thereof shall be mailed to the person operating the water-producing facility at the address shown by the district’s records. The determination made by the district shall be conclusive on all persons having an interest in the water-producing facility, and the groundwater charge, interest, and penalties thereon, shall be paid forthwith, unless that person files with the board within 15 days after the mailing of the notice, a written protest setting forth the ground or grounds for protesting the amount of production so fixed. Upon the filing of that protest, the board shall hold a hearing at which time the total amount of the water production and the groundwater charge thereon shall be determined, which shall be conclusive if based upon substantial evidence. If the water production statement was filed and the amount disclosed thereon was paid within the time required under this article, and the board finds that the failure to report the amount of water actually produced resulted from excusable or justifiable circumstances, the board may waive the charge of interest on the amount found to be due. A notice of the hearing shall be mailed to the 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, who shall have 30 days from the date of mailing to pay the groundwater charge, interest, or penalties provided under this article.

(c) Notice as required in this section shall be given by deposit thereof in any postal facility regularly maintained by the government of the United States in a sealed envelope with postage paid, addressed to the person on whom it is served at the name and address disclosed by the records of the district. This service is complete at the time of deposit.