(a) A representative of the district shall inspect the progress of work being done under a contract, and on completion of the contract, the district’s chief financial officer shall draw a warrant on the county treasurer or issue a check payable to the contractor or the contractor’s assignee for the amount of the contract price. The warrant or check shall be paid out of the construction and maintenance fund or the operating fund of the district.
(b) If the district considers it advisable, the district may contract for work to be paid for in partial payments as the work progresses. The amount of work completed at the time of the partial payment shall be shown by a certificate of a representative of the district.

(c) Nothing in this section shall affect the provisions of this chapter providing for the construction of any improvements by the United States.