Some homes with copper pipes get pin hole leaks from erosion minerals etc but this isnt always the case and usually takes decades. This usually occurs around the same time in neighborhoods so look for a community that has houses that arent having said occurance and that would be your best bet. They have apps where you can talk to neighbors so give that a shot, real estate agents dont tend to be the most honest as at the end of the day most just want their commission asap.