Galvanized water supply piping lifespan is a maximum of 50-70 years, depending on the acidity of the water it carries, and/or if it is has been used in the electrical grounding system.

The zinc coating literally washes away over time, and the steel below of course rusts, forming a plaque that can break free and enter the drinking water, causing a metallic taste, or even build up until it causes restrictions, and / or worst of all, leaks.

Thankfully, Installing it was all was almost entirely halted in the 1970's, so, it is always called out in any St Louis or St Charles home inspection that I find it in.

Many municipalities require it's replacement entirely, and I recommend the same.