an african can happily drink tap water in africa. the problem is not with the tap water it is with the drinker. the drinker does not have the immunity to the bugs that usually haunt drinking water supplies. so if you are british, the chances are that the tap water in america may not be suitable to you as you are not exposed to their bugs.
I've never had any trouble. I don't think America is very buggy. (You're talking about the USA? The same may not be true of Peru.) You can always buy bottled water if you want.
Thanks Dom Tuk. I know that Americans can happily drink their own tap water, i meant for someone from the UK going on holiday there. Sounds like it's alright...
Been to USA 5 times now & NEVER had any trouble with thier drinking water yet.
Drink it no problem as someone said here earlier, there is bottled water on sale everywhere so if not sure drink that instead.