If taste doesn't justify the price of bottled water, maybe "purity" does. Some people have the notion that bottled water is healthier than tap. We sent some bottled and tap water samples to microbiologist Aaron Margolin, of the University of New Hampshire, to test for the bacteria that can make you sick, like E. coli. "There was actually no difference between the New York City tap water and the bottled waters that we evaluated," he said.

 Some people worry about traces of chemicals, like chlorine, fluoride, copper and iron. There's a lot of misinformation suggesting tiny levels of pollutants injure people. They don't. Small amounts of chemicals are usually not only harmless, they even put them in vitamin pills.

 Many scientists have run tests that find tap water is as good for you as bottled waters that cost 500 times more. I even asked the man the bottled-water association recommended we interview, Dr. Stephen Edberg, of Yale University's School of Medicine, "Is bottled water healthier than tap?" He gave me this sparkling gem: "I wouldn't say, uh, it's healthier than tap water. I mean, uh, it's both, they both provide, uh, water."

 That's right: All those companies that charge you an arm and a leg are selling you, uh, water. I can't argue with that. They certainly are selling you water.

 If you buy bottled water because you think it's healthier than tap, test after test shows no evidence of that. And if you buy fancy brands because you think they taste better, you're probably just buying hype.