Cal. Wat. Code § 75470.5
On or before the 30th day of June of each year, the district may, by resolution of the board, fix and collect charges sufficient to meet and pay the estimated expenses and obligations, including a reasonable reserve for contingencies, of the district, until the time that money shall be available to the district from charges fixed in the next succeeding year, subject, however, to a maximum limit of two dollars and fifty cents ($2.50) upon each acre of taxable land within the district.
The board, in fixing the charges, may establish the dates of delinquency and may impose penalties for delinquency not exceeding 10 percent of the amount of the charge and may, in addition, collect interest at the rate of 8 percent per annum from the date of delinquency on all delinquent charges. The district may sue for the recovery of unpaid charges.
The revenue obtained from the charges may be used for any district purpose and the payment of any district obligation.
Ca. Water Code § 75470.5