Here are some common materials used for water supply pipes. If you have a pre-1960s house, you could still have galvanized water lines in your house. Galvanized piping has a functional life of about 40 years, according to home inspection agencies. If your galvanized steel plumbing system is approaching that age, an upgrade is probably advisable. If the pipes are still in good condition, hardware stores carry a variety of fittings and can cut and thread galvanized pipes to match your needs. 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. PVC connections are made by using a primer that softens the PVC and then applying PVC glue that melts the joints and pipe together. CPVC pipe should always be clearly labeled if used for potable (drinkable) water. In commercial applications, all piping systems are labeled. According to the International Association of Certified Home Inspectors (InterNACHI), CPVC and PVC pipes generally last for 50 to 80 years under perfect conditions, though early failure is also reported in some circumstances. As with PVC, you should use primer and glue when making a CPVC joint. Also, make sure the glue specifies that is can be used on CPVC. PEX is considered more durable than copper, with a likely lifespan of more than 50 years. For professional plumbers, PEX tubing has now largely replaced copper and other plastics used for water supply pipes. They prefer PEX because of its low cost, and because it comes in long rolls of tubing that are easy to transport. Because the flexible tubing can be bent around corners, fewer elbows and other fittings are required, speeding up installation. PEX can be joined in many different ways, including push-fit fittings and crimp rings secured with specialty PEX tools.
