The next time you're really thirsty you may want to run the tap instead of purchasing a bottle of Dasani water.

You might be surprised to learn where the designer Coca-Cola label water comes from. Forget that secret spring in the heart of the Rockies. Coca-Cola uses Calgary tap water for its Dasani label.

Spokeswoman Wendy Kuboto says the water goes through reverse osmosis. That filtering process cleans the water and then Coca-Cola adds a blend of special minerals.

The company has been in Canada for three years. It also has a plant in Brampton, Ont.

Kuboto can't reveal how much Calgary water the company uses. That's a trade secret. But, she points out, business has increased more than 100 per cent per year.

Jamie Dunn, head of the water campaign for the watchdog group Council of Canadians, says the amount of water needed to make Dasani could be putting a lot of pressure on Calgary's municipal water supply.

"They're making huge profits and how is that money being re-directed to support this system they are taking advantage of."

Dunn says people are paying 1,100 to 3,000 times more for bottled water than tap water. And, he says, it takes at least three litres to produce one litre of designer water.