Cal. Gov. Code § 8686.8
If the director determines that a local agency is financially unable to meet the matching requirements set forth in Section 8686, or unable to provide funds for replacement of a facility pursuant to Section 8686.4, the director may, if that loan would not result in a violation of Section 18 of Article XVI of the California Constitution and out of any state money made available for purposes of this chapter, lend funds, for the completion of a project or projects. The local agency shall be required by the director to make its contribution by means of deferred payments. The deferred payments shall be made in the amounts and at the times provided by the agreement executed in connection with the application, but in any event providing full repayment within 10 years, and shall include a charge to be fixed by the director in an amount estimated by him or her to equal the revenue that the state would have derived by investing the total amounts loaned at the interest rate prevailing for legal state investments as of the date of the loan.
Ca. Gov. Code § 8686.8