How to Replace a Water Shut Off Valve

Most modern homes have individual shut-off valves located near faucets and other water access points for both hot and cold water. Retrofitting has added these valves to older homes as well. The valves make it possible to repair one area in the home without turning off the water to the whole house. Turning off the water supply is necessary when fixing a damaged valve or prior poor installation. New valves are available at most hardware or home improvement stores.

Individual valves make it possible to turn water off only where necessary.
  1. Turn off the water supply to the house at the main valve, which is usually placed near the water meter that measures the amount of water used at the house. Once this is done, open the valves at all the water lines so excess water will drain from the pipes. Then close them again.

  2. Remove the supply line from the valve that runs to the sink or other water discharge area. For the best replacement connection, cut the old valve from the pipe using a hacksaw at least 1/2 inch away from the valve. Use a file to remove any burrs on the pipe after cutting, and with fine-grit sandpaper buff around the first inch of exposed pipe until it shines.

  3. Slip the compression nut from the new valve onto the piece of pipe so that the threads face the exposed end of the pipe. Slide a compression ring on and hold these in place if they are not tight enough to stay on unaided.

  4. Spread a layer of plumbing joint compound around the end of the pipe and position the new valve assembly at the pipe opening. Pull the compression nut so it meets the valve connection and hand-tighten the two together.

  5. Check the connection of the compression fitting to make sure it is seated properly and is secured evenly to the new valve. Tighten the connection completely using an adjustable wrench. Don't over-tighten because this could damage the pipe and compression fitting.

  6. Attach the supply line to the other end of the new valve, using Teflon tape over the threads to create a good seal between the two. Make sure the new valve is in the closed position.

  7. Turn the water on again at the main, and check the new connections to verify that there are no leaks. Carefully tighten any connections that may be leaking. Slowly open the new valve, and look for leaks on the supply side. Turn the water on at the faucet, and verify smooth flow without leaks.


  • Be certain that the main water supply is off while working, or it could lead to extra work at cleanup.
  • Watch when working with a hacksaw in a confined space so you don't injure yourself or cause other damage.