California Code, Water Code - WAT § 31702.3

On or before September 1 of each year, the board shall fix the rates of taxation in not to exceed four decimals, which it shall require for each of its purposes for said year, making due allowance for delinquency as fixed by law or by the board, and immediately certify said rates to the county auditor.  These acts by the board are a valid assessment of the property and a valid levy of the taxes so fixed.