Types of Plumbing Pipes
Not sure what type of plumbing pipes are used in your home? This is good information to know, as it can help you to troubleshoot plumbing issues and also make things easier when it comes time to consult a plumber for a more major repair. Plumbing pipes fall into two major categories, metal and plastic, but there are many different types in each category. Each type offers benefits and drawbacks, and some types of piping are more common than others. Here’s a look at the different types of plumbing pipes seen in today’s buildings:
- Copper: This type of pipe has been used since the early 1960s and is very reliable but expensive. Copper pipes are highly resistant to corrosion, tolerant of heat, and not prone to leaks, since the connections are soldered and fittings stay tight. Copper pipe comes in three sizes: M (very thin walls), L (medium thickness), and K (thickest walls). Types M and L are usually used for interior hot and cold supply lines, while Type K serves for underground service lines. Copper pipe’s biggest drawback is high price, which is why copper is gradually being replaced by more economical plastic pipe types. See also: Is Copper Pipe the Best?
- Galvanized Steel: These gray metal pipes are what most of us think of when we think of plumbing. They were used extensively in home plumbing in the 1960s, particularly outdoors. They were often buried and used as supply lines. Galvanized steel is only slightly resistant to corrosion and rust, and has a life expectancy of about forty years. They are usually replaced with copper or, more often, PEX and HDPE pipe in home plumbing. See also: What Is Galvanized Pipe?
- Stainless Steel: Not seen as often in household use, stainless steel pipes are strong and highly resistant to corrosion but even more expensive than copper pipes. They’re most often used in marine environments where saltwater would erode other metal pipes.
- Cast Iron: This type of pipe was frequently used in the past for drainage. It’s very durable but difficult to work with because of its weight. If you need to replace broken cast iron pipe, PVC is a good choice because it joins well with cast iron.
- Grey Plastic Polybutylene (PB): Gray or beige, usually sold in coils, this type of flexible pipe was used extensively from the late 1970s to the mid-1990s as an inexpensive replacement for copper. Over the years, however, PB has proven to be prone to leaks, which is why it’s not used much anymore.
- Creamy Plastic Chlorinated Polyvinyl Chloride (CPVC): Yellowish or beige in color, this is basically PVC pipe that has been given extra chlorination. More reliable than PB and less expensive and easier to install than copper, it can be used for cold and hot water supply. It’s more flexible than PVC but should not be buried, as it will split if it freezes.
- Polyvinyl Chloride (PVC): White or gray pipe used most often to carry high pressured water. Although it can’t be used with hot water, which can cause the pipe to warp, it’s often used for the main supply line into a home. PVC comes in sizes ranging from 1/2” to 4” in diameter, and it is inexpensive and very easy to work with. See also: Can You Repair PVC Pipe?
- Cross Linked Polyethylene (PEX): This type of pipe is used extensively for interior plumbing in new homes. PEX resists heat much better than most plastic pipe so it’s often used for water-based heating systems. See also: PEX Tubing vs. Copper Pipe: Which Is Better?
- Acrylonitrite-butadiene-styrene (ABS): This is a black plastic drainage, waste, and vent pipe that was a forerunner to PVC and is currently prohibited by many current plumbing codes. However, this piping is not uncommon in mobile homes and usually needs to be replaced with PVC or HDPE.
- High density polyethylene (HDPE): This plumbing pipe is highly resistant to corrosion, flexible, and very long lasting, and can be used to carry everything from drinking water to compressed gas to hazardous waste. HDPE comes in long lengths, and joints are formed through heat fusion, eliminating leaks. It has unusually low resistance, or drag, making it a good choice for virtually all plumbing applications.
When you make modifications or perform repairs to your household plumbing, use the same type of pipe as the original. If that’s not possible, pick a comparable type, suitable for your purpose, which will also work with your existing pipe. Make sure you understand the advantages and limitations of each type of plumbing pipe, and you’ll be able to choose what’s best for your job.