What is PEX piping?
PEX (cross-linked polyethylene) is a flexible plastic water supply tubing commonly used in home plumbing systems, especially for repiping work in place of copper or galvanized steel.
PEX stands for cross-linked polyethylene, a plastic tubing material that has become standard in residential plumbing. Unlike rigid copper or galvanized steel pipes, PEX flexes and bends to fit tight spaces, reducing the number of joints and fittings needed in a water supply system. This flexibility makes installation faster and often reduces labor costs.
The tubing comes in three color varieties. Red PEX carries hot water, blue PEX carries cold water, and white PEX can be used for either. This color coding helps plumbers quickly identify which lines serve which purpose during installation and future repairs.
PEX is durable in most home water conditions and resists freezing better than copper because the material can expand without cracking. It works well in both new construction and repiping projects, where old copper or steel lines need replacement. The tubing typically requires either crimping or expansion fittings to secure connections, depending on the specific system type.
Because PEX does not corrode like metal pipes and handles chlorinated water without degradation, it has proven reliable for decades in the field. Most water heaters, supply valves, and fixtures work seamlessly with PEX connections.