Which material is most commonly used for water supply lines in modern plumbing?

The most commonly used material for water supply lines in modern plumbing is PEX (cross-linked polyethylene). PEX is favored for several reasons. Its flexibility allows for easier installation in tight spaces and makes it less prone to damage from freeze-thaw cycles compared to rigid pipes. Additionally, PEX is resistant to corrosion and scale, which can improve the longevity and quality of water supply systems.

Furthermore, PEX does not require the use of joint fittings for bends and turns, reducing the number of potential leak points during installation. It also has excellent thermal properties, maintaining temperature when hot or cold water runs through it. These attributes make PEX a superior choice for residential and commercial plumbing applications in contemporary installations.

Other materials such as cast iron, PVC, and galvanized steel do have their uses but are not as commonly utilized for water supply lines in modern plumbing. Cast iron is typically used for drainage systems, while PVC is more often employed for waste and vent lines. Galvanized steel, although used in the past for water supply, is now less favored due to its susceptibility to corrosion over time.