How To Replace A Water Shut-Off Valve | 8 Steps Beginner Guide

How to Replace a Water Shut-Off Valve

Water shutoff valves are an important part of a toilet or sink fitting; meant to prevent backflow from mixing clean water with dirty water. This allows your tap water in your sink, as well as the water in your toilet bowl to always be clean and never full of contaminants. Shutoff valves connect to the ground or wall of your kitchen or bathroom, and connect to your sink or toiler on the other end. Most valves are made of one of two materials: stainless steel and brass.

If you experience dirty running water from your sink or toilet, that could be a sign that your current water shutoff valve has failed. In case this happened, you will need to replace it. Rather than hire a plumber, though, this can be a fix that might not be easy, but it can save you loads of money if done right.

In this article, we will show you how to replace an old shutoff valve with a new compression-fitted valve. This small project can take anywhere from one hour to three or four. No assistance is required or necessary, unless you are not sure about the steps you need to take towards installing a new shutoff valve.

For this project, you will need the following items:

  • A wrench (preferable an adjustable one)
  • Tongue and groove pliers
  • Hacksaw, pipe cutter, or PVC cutter
  • Sandpaper or steel wool
  • Rags, clothes, or towels
  • A bucket (for water to go in when you disconnect supply lines)
  • And a flashlight

Without further ado, here are the steps to take to replace an old shutoff valve with a new compression-fitted shutoff valve.

Step By Step Guide For Replacing A Water Shut Off Valve

Important: Most of the steps in this tutorial cannot be undone. If a major problem or error occurs, contact a professional plumber to help you as soon as possible.

Step 1 - Turn off your water supply

The water supply to your house should be found either in your basement or garage. Be sure to turn this off before proceeding to the next step.

Turn off water supply

Step 2 - Remove the old valve

Return to your sink or toilet. The valve will either be screwed on, compressed on or have a soldered connection. With your tongue and groove pliers, remove the valve, but don’t throw it away.

remove old water valve

Step 3 - Unscrew and disconnect the supply line or lines

If your valve is screwed on, unscrew it with a wrench take off the line that connects your toilet or sinks to the wall or floor.

If your valve is compression-fitted, you can also possibly unscrew it. Twist the nut using your wrench. To not yank and damage the line behind the wall, hold the stub of the pipe with another wrench. Twist and tug at the old fitting until it comes off. If there is a compression ring remaining on the pipe, slide it on off. 

disconnect water supply line

If the ring is made of metal and you are having a hard time removing it, leave it there. You can use it with your new shutoff valve.

If your valve is soldered, you will need to cut the pipe underneath the existing valve. Tools for this job include a pipe cutter, a PVC cutter or a hacksaw. Try making a straight enough cut across the pipe. Don’t cut it too close to the wall, or else you will not be able to install your new valve. After removing the old valve, you would be installing a new valve with a compression-fitted one.

Step 4 - Buy a new water shutoff valve

Visit the hardware store to purchase a new valve. Do not buy one beforehand, unless you know for certain which kind you need to buy. You would like a valve that best fits your pipe’s diameter. 

Buying one that is too big or too small for your pipe will not work. Be sure to bring your old shutoff valve with you, so that you know which size valve to buy.

new water shutoff valve

Step 5 - Return home and prepare to install the new valve

Clean the pipe, especially the end of it, with steel wool of sand paper. This will ensure that the valve will manage to fit without getting stuck or unable to put on the pipe. Then, slide the compression but over the water line, followed by the compression ring, and then the new valve. Position the handle so that you can easily use it for future use.

Step 6 - Fasten the compression nut

Tight the compression nut snugly against the valve. Use your wrench in order to do so. You can also use pipe joint compound on the threads of the nut for added security.

Step 7 - Reconnect the supply lines

Fasten the supply lines back from the valve to the sink or toilet. Be sure that it is securely on and will not force itself off from a flow of water.

Step 8 - Turn the water supply back on

water supply back on

Go into your basement or garage to turn on the water supply. To check for possible leaks, turn on your sink or flush your toilet to see water running. If you notice any leaker, tighten the connection more. If this does not stop the leak, turn off the water supply and inspect your toilet or sink’s fitting for possible problems.

If your installation is successful, your water should be clean and not have any weird colors to it. There is no need to adjust anything on the shutoff valve or activate any switches, you should have a valve that works and will continue to do so for a number of years.

 Are you looking to buy a new water shutoff valve? Need any more information about how they work? Got any questions or concerns? Let us know in the comments down below. We love receiving your feedback.

About the Author Juan Williams

Leave a Comment:

Dennis Sanchez says July 17, 2019

I never knew that valves were important in preventing backflow in toilets and sinks. I have noticed that the water coming out of my sink looks pretty dirty. I should probably contact a company to come and check on my valves to make sure they are functioning properly.

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