What is PEX piping?
PEX is a flexible plastic tubing made from cross-linked polyethylene, widely used in residential water supply lines as an alternative to copper or PVC pipe.
Cross-linked polyethylene (PEX) tubing is a plastic water supply pipe that has become standard in residential plumbing. The cross-linking process creates a durable molecular structure that allows the material to flex without kinking, making it easier to route through walls, crawlspaces, and tight corners than rigid copper or PVC piping.
PEX comes in color-coded rolls, typically red for hot water and blue for cold water, which helps plumbers identify lines during installation and repairs. It connects to fixtures and other pipes using specialized fittings, including compression, crimp, and push-to-connect styles. The tubing expands slightly when water freezes, reducing burst risk compared to copper in cold climates.
Residential plumbers often choose PEX over traditional materials because it installs faster than copper, requires fewer fittings than PVC, and does not need soldering. It works well for both new construction and repiping projects. PEX is not suitable for outdoor above-ground use due to UV degradation, and some jurisdictions have specific requirements about oxygen barriers and certifications for PEX systems.