Cal. Public Utilities Code - PUC § 29570. Section 29570.
From and after the date of annexation the board of directors of the district shall levy upon all of the property in the county annexed such taxes, tolls, or charges as are necessary to provide funds for the payment of the indebtedness assumed by the county or otherwise necessary to comply with the terms and conditions of the annexation agreement, all in addition to the general district taxes authorized elsewhere in this part to be levied and collected.