Galvanized steel potable water supply and distribution pipes are commonly found with nominal pipe sizes from 3?8 inch (9.5 mm) to 2 inches (51 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, valves, 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 sprinklers and natural gas. Źródło: https://en.wikipedia.org/wiki/Plumbing
In addition, home handymen often deal with repairs washing machines standing in a bathroom or dishwashers standing in the kitchen.
In the phone book you can find phone numbers for such branches emergency hydraulic, which are open around the clock and seven days a week, including holiday periods.But keep in mind that employees emergency hydraulic refuse to come to such repairs, which need not be performed immediately..