A home's plumbing system uses different kinds of pipes for various functions, such as fresh water supply, waste drainage, irrigation, gas pipes for appliances, etc. In new constructions, plastic pipes of various types are generally used, as opposed to an older plumbing system that may be dominated by cast iron and galvanized iron pipes. Below listed are some of the common plumbing pipe materials used for water supply, gas pipelines, and drainage systems. PVC (PolyVinyl Chloride) CPVC (Chlorinated Poly-Vinyl Chloride) PEX (Cross-linked Polyethylene) Chromed brass Chromed copper Galvanized iron Black iron Copper