Here's another article about water
, this one talks about what's in the raw water supplies (prior to treatment) and also discusses how bottled water fares in comparison to regular municipal water.
The kicker WRT bottled water:
40 percent of the bottled stuff is from reprocessed municipal water. And for the other half or so that doesn't come from public water supplies? Well, in general, municipal water supplies are much more tightly regulated and monitored than bottled water products (see table below). And, given the paucity of data on bottled water, it's a safe bet that you're better off with tap water even if it means we should still take steps to ensure its safety.
So, many water bottlers just take a half-penny's worth of tap water, run it through a filter, put it in a 5-cent plastic bottle (made from oil), and voila! they can sell it to you for $2. That's a pretty good racket!
Every time I see someone with a fancy bottle of imported water I remember a story from my Environmental Microbiology professor at CU. The prof had been asked to test a bottle of water that was supposedly "Pure" and "from the headwaters of the Ganges River" that a Boulder guru was selling his followers for about $15/liter. The prof did a culture on the water and found something like 15,000 times the amount of bacteria that's allowed in tap water. But since its bottled, its not regulated though...
In Europe where the tap water can be pretty crappy, there's a good reason to drink bottled water. Here at the headwaters of major rivers, it doesn't get much better than what we've got. And if a little chlorine taste bothers you, just pour a pitcher from the tap and let it sit out overnight or run it through a Brita filter.