Cal. Water Code § 31634.5

Except as provided in Section 31636, each producer, on or before the dates when the assessment or installments thereof are due and payable, shall file with the district a sworn statement setting forth the total quantity of water production in acre-feet which is subject to the replenishment assessment. Such production shall be reported as of the end of the month immediately preceding the payment date. The statement shall be on a form prepared by the district, and to the extent practicable, shall identify separately the production from each well or other water-producing facility. The statement shall also include a general description or number locating such well or water-producing facility, the method or basis of the measurement or computation of production, and such other information as the district may require.