Editing Plumbing (section)

==== Steel ====
{{Main|Galvanized pipe}}
[[Galvanized steel]] potable water supply and distribution [[pipe (material)|pipes]] are commonly found with [[nominal pipe size]]s from {{convert|3/8|in|mm}} to {{convert|2|in|mm}}. It is rarely used today for new construction residential plumbing. Steel pipe has [[National Pipe Thread]] (NPT) standard tapered male threads, which connect with female tapered threads on elbows, tees, couplers, [[valve]]s, and other fittings. Galvanized steel (often known simply as "'''galv'''" or "'''iron'''" in the plumbing trade) is relatively expensive, and difficult to work with due to weight and requirement of a [[pipe threader]]. It remains in common use for repair of existing "galv" systems and to satisfy [[building code]] non-combustibility requirements typically found in hotels, apartment buildings and other commercial applications. It is also extremely durable and resistant to mechanical abuse.  Black lacquered steel pipe is the most widely used pipe material for [[fire sprinkler]]s and natural gas.

Most typical single family home systems will not require supply piping larger than {{convert|3/4|in|mm}} due to expense as well as steel piping's tendency to become obstructed from internal rusting and mineral deposits forming on the inside of the pipe over time once the internal galvanizing zinc coating has degraded. In potable water distribution service, galvanized steel pipe has a service life of about 30 to 50 years, although it is not uncommon for it to be less in geographic areas with corrosive water contaminants.