Cal. Gov. Code § 91537.5
The bonds may bear interest on the amount or amounts, payable at the time or times, evidenced in the manner and at the fixed or variable rate or rates as shall be established by or pursuant to a method approved by the board, but the maximum rate of interest to be paid on any tax-exempt bonds shall not exceed 12 percent per annum or such higher rate as is at the time of accrual of interest then stated in Section 53531 or other applicable law. In the case of taxable bonds, or tax-exempt bonds the interest on which becomes includable in federal gross income after original issuance, the maximum rate of interest to be paid on the bonds shall not exceed 16 percent per annum. Project agreements may bear up to the same rate of interest as the underlying bonds.
Ca. Gov. Code § 91537.5