Step 8 · Turn On Water and Test for Leaks
This is the moment of truth. Place a dry paper towel under every connection you made beneath the deck. Go to the shutoff valves and turn them on very slowly, about a quarter turn at a time. This allows the lines to fill gradually and prevents a water hammer. Once the valves are fully open, use your headlamp to meticulously inspect every connection point for any signs of moisture or drips on the paper towel. Turn the faucet handles on top-side to flush any air out of the system. Let the water run for a minute, then turn it off and perform another thorough leak check underneath. Check again in an hour.