Cal. Wat. Code § 60328
The board shall authorize, and the district shall make, refunds in whole or in part of replenishment assessments theretofore paid, to any producer who has erroneously overstated his production of ground water in any sworn statement for a quarterly period required under the provisions of Section 60326, and who has overpaid his replenishment assessment for that quarter, but only upon compliance by the producer with the procedure hereinafter set forth and within the time hereinafter provided.
Any such producer, within one year of the last day for filing of the said sworn statement for the quarterly period in question, may file a verified application with the district on a form to be furnished by the district, containing such information as the district may require, requesting a refund of that portion of any replenishment assessment claimed to have been paid by reason of that producer's erroneous overstatement of ground water production. If incomplete information is contained in said application, or if the board desires other or further information than called for by that application, the same shall also be furnished by a verified statement within 30 days of mailing of written notice of request therefor to the producer at his address as shown by the district's records, or the application shall be deemed abandoned. Such request by the board shall not cause any application otherwise timely filed to be considered as not filed within said one-year period. The board may authorize, and the district may pay, any refund claimed without a hearing thereon, but no application shall be denied in whole or in part without a hearing being accorded to the applicant in which he shall have the burden of proof. Any determination by the board on any matter in connection with said application shall be final and conclusive upon the producer.
Any refund authorized to be paid under the provisions of this section may be paid only out of moneys realized from replenishment assessments levied pursuant to Section 60317, then or thereafter raised. Upon election of the producer, any refund determined by the board to be owing may be credited to the producer against any subsequent replenishment assessments which might become due and owing from him. No refunds shall be made except as authorized by this section.
Ca. Water Code § 60328