Today's Seattle Times describes bottled water and mentions that many of the the nation's mayors are suggesting we use tap water instead.
But missing from the discussion is the one difference between bottled and tap water that might matter: tap water contains fluoride (at least here in Seattle and Mercer Island). Adults with healthy teeth don't need fluoride, and young kids can get it plenty of other ways. Scientific American and others point out that many of us get too much, mostly thanks to tap water.
I just checked with Aquafina (and I'm sure the other mainstream waters are similar): they don't contain fluoride.
So my advice to anyone in government who wants to force us to give up bottled water: turn off the fluoride in the tap water first.