That's what I understand. Tap water is apparently regulated, at least in the US, under much stricter guidelines than bottled. I have also visited a water treatment facility and was quite impressed with the process they must employ to ensure the cleanest water possible. However, the process is still imperfect and they do add chlorine, but you should be able to get that out and most impurities with a cheap Brita filter. Using filtered water doesn't require running out into the cold to buy another bottle! Do beware if you have an old house...some of those houses still have lead in the pipes!