Why Is Copper Used for Water Pipes?

Copper is one of the most common materials used for water pipes because it's durable, reliable, and impermeable. Copper pipes are safe, corrosion-resistant, and last 50 to 75 years, making them a worthwhile investment compared to some other pipes used to transport water.

Copper is fairly easy to bend and work with as a material for pipes, but lead is even more pliable. Lead is so easy to work with that even the ancient Romans used it for pipes to manage water supplies. Many homes built before the late 1980s have lead water pipes, and the older the home, the greater the chance it has lead in at least some of the water pipes. More than 150 years ago, suspicions arose that lead water pipes may contribute to lead poisoning, a serious issue for children in particular.

In the late 1980s, the United States Environmental Protection Agency started coming up with regulations to reduce lead in drinking water. Among other things, an effort is underway to replace lead pipes in many cities with copper pipes. Copper pipes contain no lead, and lead-free solder has replaced the lead solder that used to be used for plumbing projects, which also helps cut down on lead that may otherwise get into drinking water. As far as metal pipes are concerned, copper is a safe alternative to pipes that may corrode and release lead into the water.

Copper pipes are durable and long-lasting compared to some plastic materials used for pipes such as cross-linked polyethylene, more commonly called PEX. Copper stands up better to heat than some forms of PEX, so it's useful for transporting hot or cold water. PEX is a fairly new product with an estimated lifespan of 30 to 50 years, which is still reasonable but not as long-lasting as copper.

PEX pipes may expand and contract, which could lead to unwanted substances seeping into them; this doesn't happen with copper. PEX also breaks down a bit if exposed to UV rays such as direct sunlight, while copper pipes are unaffected. There's also no chance of rodents chewing through copper. Though not common, rodents sometimes chew on PEX pipes in a home, which could cause major damage if they create a leak.

Copper also has a few other unique traits that make it ideal for water pipes. It's antimicrobial and naturally resists bacteria, so there's little likelihood of bacteria contaminating the water coming into your home, provided the actual water supply is of good, clean quality. Other types of plumbing pipes, such as galvanized steel, don't have this capability, nor does PEX.

Copper can't rust, while any pipe containing iron, such as a steel pipe, could rust over time. In some environments, especially over decades, iron pipes develop rust. While this may not affect the inside, rust on areas such as joints could make the pipes harder to replace. Copper also resists corrosion better than some other metals used for pipes, although acidic water could cause copper to eventually corrode.

Copper pipes are fairly easy to bend and slightly reshape without creating kinks that would affect water flow. Pipes containing iron, on the other hand, are likely to split rather than flex into a permanent bend. Copper pipes generally won't break apart except under extreme conditions, such as bending a piece of narrow copper tubing back and forth repeatedly at the same point until it creases or splits.