Water Code §51.436

(a) The district shall have an interest and sinking fund which shall include all taxes collected under this chapter. (b) Money in the interest and sinking fund may be used only: (1) to pay principal and interest on the bonds; (2) to defray the expenses of assessing and collecting the taxes; and (3) to pay principal and interest due under a contract with the United States if bonds have not been deposited with the United States. (c) Money in the fund shall be paid out of the fund on warrants by order of the board as provided in this chapter. (d) The depository shall receive and cancel each interest coupon and bond as it is paid and shall deliver it to the board to be recorded, cancelled, and destroyed.