Cal. Water Code § 74753

Upon presentation of any matured bond, or any matured interest coupon on any bond of the district, the treasurer shall pay it from the bond fund. If funds are not available for the payment of any such matured bond or interest coupon, it shall draw interest at the rate of 7 percent per annum from the date of its presentation for payment until notice is given that funds are available for its payment, and it shall be stamped and provision made for its payment, as in the case of a warrant for the payment of which funds are not available on its presentation.