Cal. Water Code § 26651

Annually before September 1st, the district’s directors shall levy an annual assessment upon the lands within the district for all district purposes in the manner provided in Chapter 2 of this part, and fix the rate of assessment as provided in Chapter 3, and shall thereupon transmit to the county auditor a statement of the rates fixed. The rate shall be sufficient to recover the expense of collection in addition to other amounts required by law. If different portions of the district require different rates of assessment the statement shall include the applicable rates for such portions. The rate shall be designated in the number of cents upon each one hundred dollars ($100), using as a basis the value of the land as assessed and equalized. The statement shall include the amount of any charges which may be added to the assessment pursuant to this division and a description of the property to which the charge applies as such property is described upon the county rolls.