Which pipe is replacing traditional copper and galvanized steel as water supply lines?

• A. PEX
• B. PVC
• C. Ductile iron
• D. Steel

Answer: (A)

PEX piping is replacing traditional copper and galvanized steel because it combines ease of installation with reliable performance in potable water systems. Its cross-linked polyethylene material is highly flexible, allowing long, continuous runs with fewer joints. That means fewer potential leak points and faster installs. PEX connections use simple crimp or clamp fittings, which also saves time and labor.

In addition, PEX resists corrosion and mineral buildup, which helps long-term reliability in various water conditions. It can carry both hot and cold water and handles temperature fluctuations well, while its flexibility helps it tolerate pressure changes and minor movement without leaking. It’s typically less expensive than copper, reducing upfront costs, and it’s quieter in operation than metal pipes.

Other options don’t fit as well for indoor residential water supply: PVC is mainly used for drain-waste-vent or cold-water distribution and isn’t suitable for hot water in many codes; ductile iron and steel are heavier, more labor-intensive to install, and more prone to corrosion or requires protective coatings, making them less economical for typical home water supply compared with PEX.