As far as tap water goes I don't use it because it does have some chemicals in it such as chlorine and flouride.
Not really an on-topic answer, but studies have shown that these bottled waters do have lower levels of chlorine, just as they advertise. But what they don't tell you is that bottled water has higher levels of coliform bacteria because of the lack of chlorine. I think I would rather have a little chlorine, thanks. There is a reason we put chlorine in tap water!
As for the fluoride, last week I saw a report by the American Dental Association (or whatever it's called) saying that the rate of tooth decay in toddlers is up in the US for the first time in over 1/4 of a century. The reason? Increased consumption of bottled, non-fluoridated water.
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Chris Harrison
San Antonio, Texas