PEX is a flexible, less expensive alternative to copper when installing water pipes. It is easy to connect copper to PEX, meaning you won't have any problems adapting your old copper pipes to PEX water pipes. PEX pipes come in different colors, making it easier to recognize which pipe is hot water and which is cold.
Benefits of PEX over Copper
Because it's so flexible and easy to use, connecting PEX to a faucet or other valve takes less time than connecting to copper. There are far less fittings required because of its flexibility, and connecting PEX to a faucet is done with a crimper, requiring no soldering. Connecting copper to PEX can be done with a push-to-connect SharkBite fitting, again without soldering. PEX is much more resistant to bursting in freezing temperatures, making it ideal for cold regions.
PEX is less expensive than copper, meaning a savings in both cost of material and labor. While hard or corrosive water can cause copper to corrode over time, PEX is unaffected by corrosive water. There were PEX pipe problems when it was first introduced, mainly complaints about leaks at the connections, which were solved with improved fittings and crimp rings. Rare PEX pipe problems include a susceptibility to rodent damage and UV damage.
Things You'll Need
Two pieces of 1/2 inch PEX piping, appropriate length
PEX pipe cutter
Two 1/2 inch x 1/2 inch PEX faucet connectors
Two crimp rings
How to Connect PEX to Faucet
Step 1: Cut the PEX Pipe
Using the PEX pipe cutter, cut the two pieces of PEX pipe to the length that you need for them to reach the faucet. Make sure that the cuts are straight. If the cut is slanted or at an angle, the crimp ring will not fit properly, possibly causing a leak at the connection.
Step 2: Crimp the Fitting
Slide a crimp ring onto both pieces of PEX. Then insert the barbed end of a PEX faucet connector into each pipe, making sure the barbed end is inserted all the way. Slide the crimp ring to the end of the pipe so that it is centered over the inserted barbed end of the faucet connector. Use the crimping tool to compress the ring. Be sure to completely compress the handles of the crimping tool for a tight seal.
Step 3: Connect to the Faucet
Turn the nuts on the faucet connectors counterclockwise onto the threads of the faucet stems with the blue pipe on the right (cold) stem and the red pipe on the left (hot) stem, if applicable. You do not need to use Teflon tape or pipe dope on the threads because the fitting contains a rubber washer that seals the connection. Tighten the nuts until they are hand tight and then snug them a 1/2 turn with the basin wrench.
Step 4: Check for Leaks
Turn on the hot and cold water shutoff valves and check for leaks. If everything looks good, turn on the faucet and once again examine the PEX fittings under the faucet for leaks. If there is a leak in a threaded nut, give it an additional 1/2 turn with the basin wrench.
Gary Sprague is a retired master plumber who now works as a writer. He lives with his family in Maine.