Cal. Water Code § 42727

To the extent that the district is indebted or has any outstanding liabilities at the time of adoption of the report, whether contingent or otherwise, the board shall levy, by order from time to time, special assessments upon the land in the district, pro rata according to the rate of assessment per acre established in the original assessment, to raise funds to pay the debts and liabilities. The provisions of Chapters 3 and 5 of Part 9 of this division shall be applicable to such assessments.