Cal. Wat. Code § 11736.5
The department may enter into banking, insurance, remarketing, and other financial arrangements as may be necessary or desirable to provide additional security for the payment of principal and interest on the bonds or to provide the holders of the bonds the right to tender bonds to the department or to another party for purchase at the times, on the notice, and on those other terms as the department may determine. These arrangements may provide for the reimbursement by the department, with interest, of moneys advanced by the provider of additional security, the provider of a tender right, the provider of moneys to fund a tender right, or anyone performing a related function, except that the interest rate on the reimbursement obligation shall not exceed the rate specified in Section 11731 and the sources of moneys for the reimbursement shall be only the sources available for the payment of the bonds.
Ca. Water Code § 11736.5