The Arizona DOT recommendations are as follows: For pipe 12 to 60 inches in diameter, after completion of the final fill and before any paving operation, the contractor shall dewater the installed pipe and provide the Engineer with either a video of the installation, a mandrel test log, or a physical measurement test log. The Engineer may waive this requirement fro side drains and cross drains that are short enough to visually inspect from the end of the pipe.