CA Pub Util Code Section 102336

In addition to the general tax levy as set forth in Section 102331, if from any cause the revenues of the district are, or are expected to be, inadequate in any year to pay the principal of, interest on, or sinking fund payments for bonds of the district as they become due, or to establish or maintain any reserve fund therefor, the board shall levy for district purposes and collect upon all property in the district taxable for district purposes as provided in this article, a tax sufficient, together with revenues already collected and available therefor, to pay the interest on the bonds that will become due and such part of the principal thereof, including any sinking fund installments required by any of the district’s agreements with its bondholders, that will become due before the proceeds of a tax levied at the next general tax levy will be available for such purposes, and sufficient to provide or to restore such reserve fund to the amount required by any of the district’s agreements with its bondholders.