1. The board of trustees shall order such amounts paid on the contract as may be certified by the chief engineer, and as may be provided in the contract covering such work, but full payment for any work to be performed by the contract shall not be made until the work has been completed and accepted by the chief engineer of said district in charge of same.

2. The said engineer in charge of the work shall inspect the work contracted for from time to time and make report thereon; and before any final settlement is made with any contractor the said engineer shall make a personal inspection of same and shall make written statement under oath that he has made such inspection and that the contractor has performed his work according to the contract.