How to Install a Shut Off Valve in an Existing Water Line

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Last Updated on September 12, 2021 by Bonnie C. Welling

Shut-off valves are very important stuff, and mostly we get their value when a water leak takes place. That’s usually when a shut-off valve can literally save from a mini-disaster. Today we will be talking over how to install a shut-off valve in an existing water line. So, if you are interested, join us and find out the actual process.

Install a Shut Off Valve in an Existing Water Line

Here’s How to Install a Shut Off Valve in an Existing Water Line.

Follow each step one by one and you should be able to install the valve yourself easily.

Identify How the Supply Lines Run.

The way your supply lines are connecting to the sink is important information you must find out first. A few would have the lines coming right through the floor. And it sticks to the faucet use. While there are also the ones that would enter from the wall behind and connect with the sink through a 90-degree upward angle on the faucet base.

With the line coming through the floor, you need straight valves. However, there are two options with behind wall lines. You can either use a straight shut-off valve as normal if the 8-10 inches of the supply line is vertically running.

Or you can opt to go with an angle stop, which is an angled shut-off valve, in case of not so long supply line. The angle shut-off will connect first with the horizontal pipe. And then it basically runs vertically with the supply line.

Preparing For The Installation.

You then need to decide about the spot where the shutoffs will get installed. And also, you must determine the distance to faucet base measurement. So that you can buy the properly sized lines.

Next comes getting the materials of the right size. Once you do so, make sure the main water supply line of your house is turned off. Then open on the faucet on the lower level. All the water lines should be running and once it completely drains, we are good to go.

Disconnecting The Line.

You also want to find the water line that’s running to the fixture base and disconnect it. There will be either soldered pipe or screwed-on attachment. You can use a hacksaw or even a pipe cutter for a soldered one.

Simply cut through the pipe in 2 spots. One is around two inches beneath the fixture base. Another one must be 6-10 inches down from the pipe. Get rid of any burrs using the pipe cutter reamer. And then use a sandpaper piece to make it smooth. You can also use emery cloth.

Tightening The Shutt Off Valve.

Let the compression nut come into the pipe from the shut-off valve, simply slide it. Make sure the threads face towards the open end. You want to slide the compression ring on afterward. Use Teflon tape for wrapping the pipe.

You can even use spread plumbing joint compound right on the pipe end. The shutoff should be on the pipe end, push it that way. then up to the shut-off valve, slide both the right and compression nut. Use hand to make the nut tight enough.

Finishing Touches.

Finally, you want to attach the flexible supply tube’s compression fitting to the shut-off valve side. Then hand tighten it. Make sure the supply tube is connecting to the faucet base with compression fitting.

Get an adjustable wrench and make sure everything is tight and firm. You don’t want to overtighten, however. In the soft copper pipe, there will be a chance of bending otherwise. Sometimes it causes damage to the compression fitting.

After this, you can turn the water on and look for leaks. You can open the valve and use your faucet as regular.

Now How to Install a Water Shut Off Valve On PEX Pipe

How to Install a Water Shut Off Valve On PEX Pipe

If you are curious about the PEX shut-off valve with drain and how it can be installed then this segment will help. You need some PEX tubing and also the crimping tool.

  • Use a PEX tubing cutter to make some clean square cut on the PEX tubing end part.
  • Next, you want to insert a brass crimp ring on the tubing.
  • The shut-off valve will have a barbed end. Put this end on the PEX tubing. You want to make it come to the valve body area completely.
  • The barbed area is where the crop ring should be placed. You can simply follow the instructions given by the manufacturer for crimping the rind right away using the tool.
  • Now turn the handle of the valve clockwise until you cannot anymore. This will make the valve close. Some may have a lever handle for the purpose.
  • Finally, turn your main water supply on and test it. There should not be any leaks at the valve. And you are done.

How to Install Shutoff Valves

Frequently Asked Questions

What Is a Shutoff Valve?

Only the ones who have never had any sort of plumbing issue in their life don’t know about a shut-off valve. It’s basically a mechanism for controlling the flow of water towards fixtures and appliances. You can use it for changing the water flow of a certain fixture without disturbing the rest of the lines in your house. Some consider adding a main water shut off valve for several benefits.

Can you replace a shut off valve without turning off the water?

It is possible to do so. But you should not try such things unless there’s no other choice. One good way is turning on other faucet and water fixtures at your home so that the specific one that you’re working with experienced reduced water pressure and it becomes slightly easier to replace the valve.

Overall Thoughts 

And that’s basically how to install a shut-off valve in an existing water line yourself. This little stuff can really help for so many safety and emergency reasons. Plus, the installation is rather simple and you should consider giving it a try.

Good Luck!

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