What is the problem with galvanized steel piping?

Galvanized steel water supply piping was a commonly used plumbing material from the 1880’s-1960’s. Initially used as an alternative to lead pipes, it was later learned that galvanized pipes heavily rust and corrode from the inside outward as the zinc coating wears off. In addition to failing and leakage, lead can also be introduced into the water supply from the galvanizing process. The expected service life of galvanized steel plumbing is around 60 years, so all galvanized steel plumbing is theoretically due for replacement by now.