You can't drink the water in the USA without getting horribly sick. Go out into the woods and drink some spring water. You're at risk of getting some nasty bacteria.
The water where in USA, which is a rather large and diverse country? And at how big of a risk?
I'm not afraid to drink unpurified water from streams in the woods here in Sweden (and no, I don't include the stream in the wood next to the local petrochemical industry in that), and have managed to do it for over 30 years without getting noticeably sick from it, as have many others.
On the other hand, I can't breathe the air here in Sweden without getting nasty viruses, as my current common cold, and the many similar ones I've had before it, clearly shows. But I still don't have any plans to start breathing my daily air through a filtered mask or from a tank.
Risk vs. reward...