The plumbing pipes are broadly divided into metal and non-metal and the materials that are most commonly used for piping are steel, copper, PVC, CPVC and PEX.
The polyvinyl chloride (PVC) pipes are used for cold water only (since hot water will warp them) and are used typically for drains; the PVC pipes are normally white or gray and are less expensive than the metal pipes.
The CPVC is chlorinated polyvinyl chloride and the CPVC pipes are capable of handling cold and hot water; one way to tell CPVC from PVC pipe is the yellow color of the CPVC pipes, their thinner walls, and the fact that they are more flexible.
PEX (polyethylene) pipes have quite a few distinctive qualities - they are not only capable of handling hot and cold water, but are also highly flexible, less likely to leak than the other non-metal pipes, and even have higher heat resistance. The PEX pipes come in three colors: creamy white, or red and blue to indicate cold or hot water respectively.
Copper has been used for plumbing pipes for a long time and gained popularity in the 60s of the previous century. What makes copper attractive is its durability and its corrosion and high temperature resistance; however, copper is also more expensive than most other types of plumbing materials and copper pipes can split in extreme low temperatures.
Steel pipes: galvanized and, less often, stainless steel is also used as piping material. The galvanized pipes are commonly found in older homes and are less often used today since they are prone to leaking and their interior to corrosion. They are slowly being replaced by PEX pipes which are just as durable and less costly.
The stainless steel pipes have limited use since they are quite expensive and are typically applied only where salt water is fed.
