How to Cap a Water Pipe With a Push-On Fitting

  • 01 of 05


    Capping a water pipe
    Aaron Stickley

    Temporarily capping a water pipe is often necessary during a kitchen or bathroom renovation. When replacing cabinets you may find that the pipes come through the back or bottom of a cabinet. If you need to remove the cabinet, you have two options: you can either cut out pieces of the cabinet so you can pull the cabinet away from the pipes, or you can cut the pipes so you can remove the cabinet while the pipes slip through the existing holes.  

    Cutting the pipes is usually the better option, and capping the pipes with convenient push-on, or push-fit, fittings is much easier than soldering on copper caps. The push-on caps temporarily seal the pipes so you can turn on the water to the rest of the house during the installation of the new cabinets.

    Supplies Needed:

    • Tubing cutter or hacksaw.
    • Emery cloth.
    • Tape measure.
    • Marker.
    • Push-on pipe caps.
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  • 02 of 05

    How to Cap Water Pipes With Push-On Fittings: Step 1

    Plumber fixing kitchen sink
    kali9 / Getty Images

    Shut off the water supply to the house. Since you'll be cutting the water pipes behind or below the shutoff valve on each pipe, you must shut off the water at the main shutoff valve. Drain residual water and pressure from the pipes by turning on an outside spigot or a faucet that is lower than the pipes you are working on (such as on a basement washtub). This minimizes the amount of water that spills out of the pipes when you cut them.

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  • 03 of 05

    How to Cap Water Pipes With Push-On Fittings: Step 2

    Clean copper pipe before capping
    Aaron Stickley

    Cut the water pipes, using a tubing cutter. You can also use a hacksaw, but be careful to make a clean, square cut to ensure a proper seal with the push-on fittings. Leave as much pipe as possible so you won't have to lengthen it later when reconnecting the fixture. Clean the end of each cut pipe with emery cloth; it must be smooth and free of old solder or other material. If you cut the pipes with a hacksaw, file any rough edges before cleaning with the emery cloth.

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  • 04 of 05

    How to Cap Water Pipes With Push-On Fittings: Step 3

    Cap water pipe with push on fitting
    Aaron Stickley

    Measure from the end of each pipe and make a depth marking, using a marker, as directed by the push-on fitting manufacturer. The mark will tell you when the fitting is pushed on all the way, which is essential for a proper seal. Push the pipe cap onto the pipe until its edge reaches the depth mark.

    Note: Push-on fittings work for copper, CPVC, and PEX water pipe. Most include a stiffener—a small plastic cylinder—that slips into the end of the pipe to provide rigidity to PEX tubing. It is not required with copper or CPVC pipe, but you don't have to remove it when using these materials.

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  • 05 of 05

    How to Cap Water Pipes With Push-On Fittings: Step 4

    Cap copper pipe with push on fitting
    Aaron Stickley

    Turn the water back on and check the cap connections for leaks.

    Push-on fittings can be temporary or permanent. Most include a release feature that allows you to remove the fitting with a special tool, usually a simple plastic device that you push against the fitting to depress a release collar, allowing you to slip off the fitting. Always use the manufacturer's tool to remove the fittings.