I work for a large municipal water system. Almost always, copper corrosion is caused by water chemistry, primarily low pH. Low pH water is very aggressive and erodes the protective oxide film that copper has, same with lead (what happened in flint is they did not have corrosion control)
In about 1995 the EPA had the lead and copper rule, requiring testing certain homes (depending on when built) for corrosion issues. We started corrosion control in 1999 and we raise the pH from about 8-.0 to 8.5. Testing since then shows it has been very successful.
Its not an electrical issue, I have the definitive study from the AWWA, that shows that. Your plumbers can always add a length of PVC pipe on the service line to isolate it if its is metallic to the water main.
And have them do this, check with their water provider, ask for the consumer confidence report, look for the information on lead and copper.
Or if on a private system have a water test done.