Install Shut Off Valve Under Sink & Replace Faucet

Your faucet drips or leaks, so time to repair or replace it. Yet the only water shut-off is located underneath the home. “What a pain,” you say to yourself. Next time avoid the hassles by installing separate shut-offs to each plumbing fixture. Just remember that you need a shut-off on both the hot and cold waterlines.

To replace a kitchen or vanity faucet and add a shut-off valve, just follow these steps:

Shut off the water to the whole house than take the pressure off the water lines. Opening up the outside spigot is a great way to relieve the pressure. That way when you cut into the water line, you won’t get a face full of sprayed water. The main shut-off is usually located either by the water heater, or underneath the home.

Install Shut off Valve Replace Faucet

Remove the old faucet by unscrewing the waterlines, then unscrewing the mounting nuts. The picture shows a close-up of a mounting nut. Often times you can just reach up and turn-off the plastic nuts by hand. The metal nuts will require a wrench or slip-joint pliers.

Faucet Replacement

Cut off the ends to the old waterline about 12 inches back or so. If you have white Pex or gray Poly waterlines, a plastic tubing cutter works well.

Install Shut off valve

Locate the materials needed (pictured from left to right for connecting your faucet to existing gray poly waterlines) – 1/2″ poly crimp ring, 1/2″ pex to poly transition fitting, piece of white pex waterline with two 1/2″ crimp rings, 1/2″ pex to 3/8″ male shutoff valve, 16″ or 20″ flexible faucet connector. If you already have white PEX waterlines, then all you need is the shut-off valve and the faucet connector. The existing PEX waterline will crimp right to the shut-off valve.



Assemble the pieces. Using a 1/2″ crimper, crimp the rings to the white Pex. Screw the faucet connector to the shut-off valve. Don’t overtighten. Thread paste or tape is not needed. I have new 1/2″ and 3/4″ crimpers available for $95 by emailing me. $125 may sound expensive, but as little as 3 months ago, the price was double. One call to a plumber would pay for the cost of this easy to use tool.

Install new faucet

Mount the faucet to the sink as per manufacturer instructions.

Mount Faucet

Then screw-on the hot and cold waterlines. Don’t overtighten. Thread dope or tape is not needed. The picture shows how the connectors should be screwed on, although you’ll do the fastening underneath the sink. Fasten the sprayer too, if included.

Screw On nut

Crimp the new connectors/shut-off valves to the existing water lines.



Turn on water and check for leaks.

Install Shut Off Valve and Replace Faucet Complete!


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