All construction contracts of the district, which shall be let solely by the district shall comply with state purchasing and bid laws and the board of directors of the district shall award the contract pursuant to state purchasing and bid laws. The contractor will comply with the terms imposed by such board and enter into bond with sufficient sureties, to be approved by the board, in such penalty as shall be fixed by such board, but in no case to be less than the contract price, conditioned for the prompt, proper, and efficient performance of the contract.