California Code, Water Code - WAT § 71687.2

If the board determines that a replenishment assessment should be levied upon the production of ground water from ground water supplies within the district during the ensuing fiscal year, then immediately following the making of such determination the board shall levy a replenishment assessment on the production of ground water from the ground water supplies within the district during the fiscal year commencing on July 1st next, and such replenishment assessment shall be fixed by the board at a uniform rate per acre-foot of ground water so produced. The producers of such ground water shall pay such replenishment assessment to the district at the times and in the manner hereinafter in this article provided.