How to Replace a Compression Fitting on a Water Shut Off Valve For a Faucet

Turn off the main water supply to the house. The main shut-off valve is between the water meter and your home. Often the shut-off valve is near the water meter.

Open the faucet with the leaky shut-off valve and allow all the water to drain from the line. Turn the connecting end of the faucet water supply line, where it connects to the shut-off valve, counterclockwise with a wrench and remove the line from the shut-off valve.

Turn the compression nut securing the shut-off valve to the house line clockwise with a wrench. The nut is turned clockwise because you are looking at it in reverse. The nut threads onto the shut-off valve. Continue turning the nut until the shut-off valve is free of the house line.

Pull the existing compression ring fitting off the end of the house pipe. A pair of pliers may be necessary to twist the ring off the pipe. Slide the compression nut off the house pipe.

Clean the threads on the shut-off valve, removing all traces of old plumber's tape. Wrap new plumber's tape clockwise around each set of threads.

Slide a new compression nut over the house pipe with the threads of the nut pointing away from the pipe. Push a new compression ring fitting over the end of the house pipe. The concave portion of the ring should point away from the pipe. Some compression rings are concave on both sides. Push the ring ¼ inch past the end of the pipe.

Position the end of the shut-off valve against the end of the house pipe. Slide the compression nut over the threads of the shut-off valve and tighten the nut until it is hand tight. Ensure that you hold the shut-off valve against the end of the house pipe while tightening the nut. The nut draws the compression ring against the end of the shut-off valve threads forming a watertight seal.

Turn the compression nut another 1/2 turn with a wrench. Thread the water supply line connecting nut onto the shut-off valve until it is hand tight. Turn the nut another 1/2 turn with the wrench. Turn off the faucet, and rotate the shut-off valve handle clockwise until it stops.

Go to the main water shut-off to the house and turn it back to the "On” position. Slowly turn the faucet shut-off valve counterclockwise to supply water to the faucet. Check for leaks at the connections and turn the nuts an additional 1/4 turn if necessary.