Temporarily capping water-supply pipes is often necessary during a kitchen or bathroom renovation. For example, when replacing cabinets you may find that the water supply pipes extend through the back or bottom floor of a sink cabinet. Rather than cutting out a large section of the cabinet to remove it, it is usually far easier to cut off the ends of the pipes and cap them with easy-to-use push-on fittings, which will work with copper, CPVC, or PEX plumbing pipes.
Push-on fittings are made by several different manufacturers—one of the most popular is SharkBite, a name that has become synonymous with this fitting style. Rather than using mechanical or soldered connections, they work via a system of internal seals and sharp barbs that grip the pipe securely. Push-on fittings are now allowed by nearly all plumbing codes across the country.
Equipment / Tools
- Tubing cutter or hacksaw
- Metal file (if needed)
- Tape measure
- Emery cloth (if needed)
- Push-on pipe caps
Shut Off the Water
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 into them.
Cut Off the Pipes
Cut off the water pipes, using a tubing cutter if you have enough room to rotate the tool around the pipe. 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 add an extension later when reconnecting the fixture.
Clean the Pipe Ends
Clean the end of each cut pipe with a rag. It must be smooth and free of old solder or other material. If you cut the pipes with a hacksaw, file off any rough edges before cleaning. If necessary, you can smooth rough surfaces with emery cloth, but be careful not to sand down the pipe; it should have its original roundness and diameter to ensure a proper seal with the push-on fitting.
Cap the Pipes
Measure from the end of each pipe and make a depth marking, 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.
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 when you are capping PEX tubing. The stiffener is not required with copper or CPVC pipe
Test the Capped Fittings
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, which is usually a simple plastic device that you push against the fitting to depress a release collar and slip off the fitting. Always use the manufacturer's tool to remove the fittings.