Pipe materials
In old construction, lead plumbing was common.

 It was generally eclipsed toward the end of the 1800s by galvanized iron water pipes which were attached with threaded pipe fittings. Higher durability, and cost, systems were made with brass pipe and fittings. Copper with soldered fittings became popular around 1950, though it had been used as early as 1900. Plastic supply pipes have become increasingly common since about 1970, with a variety of materials and fittings employed. Plumbing codes define which materials may be used, and all materials must be proven by ASTM, UL, and/or NFPA testing.