How to Install PEX Plastic Water Pipes

PEX water pipes are made of cross-linked polyethylene for both strength and flexibility. PEX is available in red, blue and clear pipes. This allows you to use red for hot water lines, blue for cold water lines and clear for under floor heating systems. PEX pipes attach to fittings to turn the flow of water or they are used as a main line with several other lines feeding out to the home. There are two kinds of fittings that include the crimp and quick connection fittings. The quick connection fittings do not require any special tools.

A crimper is required for crimp fittings on PEX water pipes.

Things You'll Need

  • Measuring tape

  • Tubing cutter

  • Fittings

  • Crimp rings

  • Ring crimper


Step 1

Measure the length of PEX pipe needed for your project with a measuring tape. Mark the pipe with a pen at the length needed.

Step 2

Place a tubing cutter on the mark and hold it at a 90-degree angle to the pipe.

Step 3

Squeeze the tubing cutter and turn it in a circle around the pipe perimeter. Keep squeezing the cutter and rotating it in a circle until it cuts through the pipe.

Crimp Fittings

Step 1

Slide a crimp ring onto the pipe end to receive a fitting. Fittings can form a "T" for one water line in and two water lines out or an angle to turn the water flow in any direction.

Step 2

Insert the pipe into a crimp fitting as far as it will go.

Step 3

Slide the crimp ring over the junction of the pipe in the fitting. Place a crimper over the ring and squeeze the handles to set the crimp ring.

Quick Connection Fittings

Step 1

Hold the PEX tubing in one hand and the quick connection fitting in the other hand.

Step 2

Push the tubing into the quick connection fitting as far as it will go. There is some resistance so the tube has to be pressed very firmly. There are stainless steel teeth inside of the fitting that grasp the tubing and hold it in place.

Step 3

Pull the tubing and fitting with one in each hand to make certain the fitting is seated on the tubing. There should be no movement of the tubing. If the tube moves, push the collar toward the fitting with that hand and pull the tubing out. Release the collar and insert the tubing deeper into the fitting with firm pressure.


All PEX ends that insert into a fitting must be made at a 90-degree angle and burr free to fit correctly in the fittings and hold without leaks. You may cut the pipe with a handsaw at a 90-degree angle and then de-burr the ends with a pocketknife. De-burring is removing the cut plastic caused by a saw so that the cut is clean and smooth.

Use 90-degree corners to bend the PEX into the right shape without depressing the pipe and reducing water flow within it. These angles are plastic and simply press onto the flexible pipe.