Step 7 · Reconnect Supply Line and Test for Leaks
First, ensure the new angle stop is in the 'off' position (the handle should be perpendicular to the pipe for a quarter-turn valve). Re-attach the faucet supply line to the top outlet of the new valve. Hand-tighten the nut, then give it a gentle quarter-turn with an adjustable wrench. Now, go back to your main water shutoff valve and turn it on slowly to re-pressurize your home's pipes. Return to the sink and carefully inspect the new valve, especially around the large compression nut at the wall. Use a dry paper towel to wipe the connection; it will make even the smallest drop of water visible. If there are no leaks, slowly open the new angle stop by turning its handle counter-clockwise. Once open, check all connections again for leaks: the main connection at the wall and the supply line connection. Finally, turn on the faucet to test flow and check for any drips under the sink. Dry everything thoroughly and monitor for the next hour.