Philip C. Singer, PhD Responds:

Philip C. Singer, PhD, the Dan Okun Distinguished Professor of Environmental Engineering in the school of public health at the University of North Carolina at Chapel Hill, responds: There is no proof that bottled water is any safer than tap water, although in many cases it may taste better. In fact, tap water is subjected to more-stringent regulations by the EPA than bottled water is, which is regulated by the FDA.

Tap-water quality must meet regulations for more than a hundred potential contaminants in order to protect public health. Your water company must also provide an annual consumer confidence report to all its customers, explaining how its tap water compares with the regulated levels of each potential contaminant. In many cases, bottled water is taken from the same sources—and contains many of the same impurities—as tap water. Often, however, bottled water is processed by more-sophisticated, and more-costly, technologies. Although, these technologies don't necessarily make the water any safer.

Tap water is distributed through a complex network of pipes, so chemicals must be added to the water after treatment to protect it from recontamination and to preserve water quality. Bottled water, of course, has a very different system for distribution to consumers, and the preservation of water quality is much simpler. But the bottom line: Don't confuse taste with safety.