Materials Used in Water Supply Pipes

Copper

The Spruce / Kevin Norris

Copper pipe is mostly used for hot and cold water distribution, as well as being regularly used in HVAC systems for refrigerant lines. Although once used in gas piping, this is no longer allowed in some jurisdictions. Copper piping works in both underground and above-ground applications, but copper can be affected by some soils and it should have a protective sleeve if used underground.

For many years, copper was the gold standard for water supply pipes, as galvanized steel fell from favor. Copper plumbing pipes can last for up to 50 years, but as it ages, copper thins out, eventually leading to pinhole leaks. More recently, various forms of plastic have replaced copper as the favorite, though copper pipes and fittings are still widely available. Due to the price of copper and the longer labor needed to install, many builders have switched to alternative water distribution piping, especially PEX. Depending on the city you live in or commercial versus residential applications, copper is still used widely over CVPC and PEX tubing.

Copper comes in different thicknesses which are labeled M, L, and K. M is the thinnest grade of copper. Copper can be connected in different ways, including compression fittings, push-fit fittings, or sweat-soldering. K copper is used in underground applications and high pressure situations. M copper tube is used in heating applications and isn't allowed for water lines in some jurisdictions because it cannot withstand high pressure water.