I think it is probably good form to filter home water whether it is city water or well water. Capturing rainwater and having some kind of back up system in place would be good. That said, a water contamination problem where filtering/boiling won’t help may be something that we have to just accept as outside our control unless we have the resources to do something extreme.
I try to keep the Serenity Prayer in mind as far as prepping goes.
God grant me the peace to accept the things I cannot change, prep for the things I can and the wisdom to know the difference.
😉