Santa Clara Valley Water District’s fact page on bottled water:
In addition to the misconception about health benefits, there are other, more serious, problems associated with the production and consumption of bottled water. According to the Beverage Marketing Corporation, Americans bought a total of 31.2 billion liters of water in 2006. The Pacific Institute estimates that producing the bottles for American consumption required more than 17 million barrels of oil, not including the energy for transportation. Bottling the water produced more than 2.5 million tons of carbon dioxide. It took 3 liters of water to produce 1 liter of bottled water.
More at the site.
See also: Bottled Water: The Hoax