When I lived in Warsaw tap water tasted like public swimming pool water after boiling old shoe for an hour.

No need to resolve to anti-americanism, water is fine where I live, it just tastes better with a filter

Filters can get rid of unwanted minerals and some machines like espresso machines require cleanest water. I have some of the best tasting drinking water in the world, almost iceland level but it has high limestone content and I need to filter it twice for my espresso machine.

Some European tap water is disgusting, I’m sorry to inform you