We think of ourselves as shrewd and thrifty shoppers. Yet when it comes to bottled water, North Americans are conned to the tune of $15 billion and eight billion gallons annually, paying twice for a commodity we already own.

The truth is most of us in the United States and Canada can be assured that the water that flows from our taps is as clean as bottled water – and our taxes have already paid for it.

In fact, tap water may actually be cleaner. Last month, researchers found that some bottled water contains more bacteria than tap water. More than 70 percent of the popular brands tested in this new study failed to meet bacterial standards set by the United States Pharmacopeia, a non-governmental agency that sets safety standards for medications and health-care products, reports The Montreal Gazette.

In comparison, tap water is usually so pure, bottled water companies can simply bottle it and sell it to you.

Today, the U.S. and Canada spend enormous sums of money on research and regulations to keep tap water safe. The Colorado-based Water Research Foundation, the world’s largest non-profit organization dedicated to drinking water studies, is bankrolled by about 900 water utilities, and spends $20 to $25 million a year on its research, which is used by the U.S. Environmental Protection Agency and Health Canada, and by water utilities serving roughly 80 percent of the U.S. population.

The bottled water industry possesses no such research arm. Nor is it regulated as rigorously. EPA requires public water supply testing by certified labs that must give timely violation reports. Public water systems must also offer reports to customers, noting their water’s source, evidence of contaminants and regulatory compliance. In contrast, the U.S. Food and Drug Administration, which regulates bottled water, cannot require certified lab testing or violation reporting. Nor does FDA require bottled water companies to disclose where their water comes from, how it is treated, or what contaminants it contains.

Look at the historical record and you’ll see that the government regulated water systems of the U.S. and Canada are among the best on the planet, protecting against cholera, typhoid and other water-borne epidemics that still plague the developing world. Unfortunately, the success of these utilities has made them largely invisible. It’s like mass vaccinations – when the threat of a deadly disease is eliminated, we quickly forget how we achieved public health in the first place, and then take it utterly for granted.

Fifty years ago, when the American public started to worry about a clean environment, including their drinking water, they didn’t suddenly start buying bottled water. Instead they demanded action and the Clean Water Act was passed – a regulatory framework that dramatically improved drinking water standards in the 1970’s, and still does today.

Still, there’s an appropriate market for bottled water. Take lead contamination. It’s a big deal in some schools where old pipes leach toxic lead into tap water. In such cases, bottled water is an affordable substitute to keep students safe. Even mundane problems, like the inconvenience of a suddenly thirsty child, makes bottled water a better choice than a sugary drink.

I’m not saying that bottled water is inherently evil, just mostly unnecessary and a waste of money.

If you want to pinch pennies in these hard economic times, why pay up to 36 times more for bottled water that may or may not be just as good as your own tap water?

JUDE ISABELLA is a science writer and managing editor of YES Mag, the Science Magazine for Adventurous Minds. (c) 2010 BlueRidgePress.com