The county treasurer shall be the custodian of the funds of the irrigation district. He or she may designate 1 or more of his or her deputies who may act for him or her in the performance of any of his or her duties under this section. The irrigation board may require the county treasurer and any deputy county treasurer, so designated, to furnish a bond payable to the irrigation district, in addition to any bond payable to the county, conditioned upon the faithful discharge of his or her duties in respect to money belonging to the irrigation district, the premium on the bond to be paid by the irrigation district. Money held by the treasurer shall be paid out only upon order of the irrigation board, except that an order shall not be required for the payment of principal and interest on bonds.