Cal. Water Code § 42729

If for any reason funds are not available to the district to defray all expenses under this article, as estimated by the board to be incurred for the general benefit of the district up to the time that a new assessment for the new project has been levied and become available under Chapter 2 of Part 9 of this division, the board may levy assessments from time to time pursuant to Chapter 1 of Part 9 of this division to raise the necessary funds to defray such expenses.