California Code, Public Resources Code - PRC § 9501

The directors shall, on or before January 1 of the calendar year during which an assessment is to be levied for the first time, notify the State Board of Equalization as provided in Revenue and Taxation Code Sections 756 and 759 and, annually on or before August 1st, furnish the county auditor and the board of supervisors an estimate in writing of the amount of money necessary to be raised by assessment for the purposes of the district for the next ensuing fiscal year.