Well, nothing surprises me any more and everybody probably knew this way before me, but whenever I purchase a bottle of Dasani or Aquafina (the Dutch girl in me likes their value for the money), I am drinking someone else's tap water. Yeah, they may call it "bottled purified water, " but it's just plain old water from a public water source put through a series of filters. And the practice is perfectly legal.
So, I've begun to fill my empty Aquafina and Dasani bottles with my own tap water run through my own filters. Frankly, I can hardly tell the difference.