I would ask your friends what evidence they have to support their opinions. They will be unlikely to produce anything besides conspiracy theory level information. It’s similar to the vaccine debate. Who do you believe? The large, established scientific community, or your friend’s hunch?
Tap water is regulated by state and federal governments for safety. Virtually all tap water in the US is absolutely safe to drink. Filters can improve taste, which is impacted by many factors, but neither home filters nor boiling would remedy a Flint, MI type contamination.
Mistrusting tap water would mean mistrusting our regulatory bodies (tempting right now, understandably) - but to do so would impact so much more than your tap water. It would be like rearranging deck chairs on the titanic to filter your tap water if you believe the the functionality of our government has so degraded. Meat, milk, household cleaners, detergents, eggs, bottled water, packaged and caned foods — all and more would also be compromised by regulatory corruption.
Also, the poor, hospitals, etc. depend on tap water — if it’a not safe, shouldn’t your friends and fellow citizens be more outraged? Even if they filter or boil it, they still pay for the water, shouldn’t they protest or complain to their provider?
US tap water is safe, drink away.