Three eras of pipe, one neighbourhood
Copper, from the earlier houses. Copper became the standard supply material through the 1950s and 1960s and it is long lived. It splits when it freezes, and after several decades it can develop pinhole leaks where water chemistry or flow velocity has worked on the inside of the pipe. A copper line that failed from a freeze is usually a straightforward section replacement rather than a repiping discussion.
Polybutylene, from the later ones. This is the one worth paying attention to in a neighbourhood with housing from the late 1970s through the mid 1990s. Polybutylene is a grey, sometimes blue, flexible plastic pipe installed widely in American homes during that window, and it has a known record of failing at its fittings rather than along the pipe. If a house here has grey plastic supply pipe and has already had one leak, the pattern usually continues, and replacing the system is a more honest answer than repeated repairs. See burst pipe replacement.
CPVC and PEX, from renovations. Rigid cream plastic and flexible coloured plastic turn up wherever a bathroom or kitchen has been reworked. Each junction between two materials is a potential failure point, which is why a burst at a transition is such a frequent finding in houses that have been altered.
If you can tell us what colour and material your pipes are before anyone arrives, it genuinely shortens the visit.
