Poland Spring. Aquafina. Perrier. The names plastered across bottled water labels conjure purity, freshness, and nature. And the marketing has been successful: In the United States, a thousand people buy a bottle of water every second of the day, either because they prefer the taste, find it more convenient, or think it's safer than what comes out of their faucets. It's a multi-billion-dollar-a-year industry. But do we really know what's underneath those plastic caps? Irregular standards and monitoring systems mean that the water you pay for in a store isn't necessarily any better than what you get from the tap ­­-- and sometimes it's worse.

In Bottled & Sold: The Story Behind Our Obsession with Bottled Water, author Peter H. Gleick explores what may be the signature beverage of our time. He's president of the Pacific Institute in Oakland, California, and received a MacArthur Fellowship for his work on water issues. He spoke with journalist Jenny Shalant.

Many people buy bottled water because they assume it's cleaner and healthier than tap water. Are they wrong?

There's a fundamental assumption that bottled water must be safer because it's so expensive and so heavily marketed. The idea that it's safer has certainly been pushed on us by the bottled water companies. But the reality is, we don't know, because we're not looking hard enough. The regulations aren't strict enough, and enforcement isn't focused enough. When we actually look at bottled water quality and do comprehensive tests, we find problems.

You argue that the U.S. Food and Drug Administration, which currently has authority over bottled water companies, is doing a bad job. What's wrong with this system?

We have this weird situation where our tap water is regulated by the Environmental Protection Agency under the Safe Drinking Water Act, and bottled water is regulated by the FDA as a food product. The regulations for the two are similar, but there are some serious loopholes in bottled water regulation in terms of what they look for, how they enforce it, and who does the monitoring.

For example, the EPA has strict rules for how often community water systems must test tap water for contaminants such as coliforms, including the deadly E. coli bacteria. This can be dozens of times per day for big cities. But under FDA standards, bottled water must only be tested for coliforms once a week. The FDA doesn't even make it mandatory for bottling plants to send in their test results. And when tests do show that bottled water has been contaminated, the FDA doesn't enforce a recall. The bottle can still be sold as long as it's labeled as "containing excessive bacteria." Given that, I think bottled water and tap water ought to be regulated by a single agency under stricter rules than we have now.

In your book, you say that bottled water companies have actually worked to make us fear our tap water and actively discourage drinking it. Why have they been so successful?

First of all, the job of the bottled water companies is to sell us something that we can already get cheaply out of our tap. It's a hard thing to do, unless they can convince the public that the product we're drinking is somehow bad, or that the product they're selling is somehow better. And increasingly, the bottled water we buy comes from the same municipal water systems that feed our taps.

Selling bottled water requires all the tools of advertising and marketing and salesmanship that American industry has become so good at. So, for example, the bottlers have compared tap water to toilet water and mop water. They've partnered with restaurant chains to make sure bottled water is offered to the table first, before tap water. Some high-end restaurants even hire water sommeliers to help diners match different brands of water with different foods, and to boost profits. And bottled water advertisements aren't just selling you water; they sell youth, beauty, and health -- miracle cures for all kinds of ailments and modern worries.

But the news is also full of alarming stories about the poor quality of our tap water and the inadequacies of the Safe Drinking Water Act, including the recent "Toxic Waters" series in The New York Times.

There are problems, but the solution is not bottled water. It's to do a better job protecting our tap water. Eighty-five percent of our population gets its drinking water from public water systems, and in general they're very well run. The other 15 percent gets its water from private systems. For the most part, they're well run, too. I don't think we ought to be abandoning the great public water systems that we built in the 20th century and replacing them with bottled water companies that are designed to make profits rather than protect the public good.

We do look pretty carefully at the quality of our tap water. And when there's a problem, such as after a major storm, the law says that utility companies have to tell the public so that we can find other water temporarily while the water agencies fix the problem. So the news is full of bad stories about tap water. Over time, that erodes public confidence. And this is part of the reason it's so easy for the bottled water companies to sell their products.

What will it take to improve our tap water and boost public confidence in it?

In most cities, we don't adequately protect the source water, the place where our water comes from, so it requires a very high level of treatment before we consume it. And we don't adequately treat our wastewater once we've collected it. So we need to do both.

We're definitely under-investing in our tap water system. It's incredibly cheap, and we probably ought to be willing to spend more than we do for tap water, if in return the utilities promise that it's going to be good quality. The deal is: I'll pay for tap water, happily, if I know what I'm getting, and if I can trust it. And I think that's a fixable problem.

Part of the reason you argue that we need to improve our tap water systems is that the impacts of bottled water on our environment are so severe. Can you describe some of them?

First of all, it takes a lot of energy to make plastic bottles, to collect and treat the water in the bottles, to package and store the bottles, to ship them around. Secondly, the vast majority of that plastic gets thrown away. In the United States, 70 or 75 percent of it ends up in landfills; it's never recycled.

And third, we're taking more and more water out of local ground water systems to satisfy our demand for bottled water. That can have local ecological impacts and damage groundwater wells. Water is mostly a renewable resource, but sometimes when we over-pump groundwater, it's nonrenewable, just like oil. I don't think enough care has been given to ensuring that bottled water plans are done in a sustainable fashion.

Isn't drinking bottled water often unavoidable, particularly when we're on the go?

One of the reasons bottled water has become more and more popular is that it's harder and harder to find clean, working water fountains. People don't trust them. Almost anywhere you are, there's somebody selling bottled water within a few minutes walk. And so I think the convenience factor is important. First, rebuild trust in tap water, then make sure it's widely available. Make sure there are water fountains everywhere. There are lots of brilliant new designs for water fountains that are filtered and cooled.

Do you think it's possible to get rid of bottled water?

No, but we can do a lot more to move people off the bottle and back to our tap water system. And if we're serious about tackling the bad things associated with bottled water -- the environmental costs, the energy costs, the climate costs, the waste problems -- we need to deal with the reasons people buy it. And there are four: we fear our tap water, public water is increasingly hard to find and bottled water is increasingly convenient, people don't like the taste of their tap water sometimes, and marketing and advertising convinces us that bottled water is a great idea. Each of those four reasons can be dealt with, but most important is re-establishing confidence in our tap water.