Step 9 · Turn On Water and Check for Leaks
This is the most critical step. Slowly turn both the hot and cold water shutoff valves counter-clockwise to open them fully. Immediately check for any leaks at all connection points: where the supply lines meet the shutoff valves, and where they connect to the faucet's tailpieces. Use a dry paper towel or your dry fingers to wipe each connection joint. Any moisture indicates a leak that needs to be addressed by slightly tightening the connection or by disconnecting, checking the gasket, and reconnecting.