Paying extra for bottled water? You may be wasting your money, says an expert in aquatic chemistry.
Daniel Giammar, Ph.D., a faculty member in the Environmental Engineering Science Program at Washington University in St. Louis, says that tap water is just as safe to drink as bottled water. He also says that the pricey bottled water you value so highly might well be nothing more than repackaged tap water.
“I see no health benefit of any kind to bottled water,” says Giammar, who is an assistant professor of civil engineering. “The tap water we drink meets very strict standards that are designed to protect our health. These are developed over many years of study and they all include fairly large factors of safety. Any differences between tap and bottled water, in terms of health, are negligible.”
The U.S. Environmental Protection Agency (EPA), whose standards today are more stringent than ever before, regulates tap water, also referred to as municipal water. Such standards include minimum allowable levels of pathogens — inorganic and organic compounds that may be harmful to human health.
Bottled water, which is regulated by the Food and Drug Administration (FDA), meets similarly strict standards. Giammar does point out that while both types of water are safe to drink if they meet the standards set, according to the EPA, people with severely compromised immune systems and children might have special considerations when it comes to choosing their water supply.
Giammar says that bottled water can be labeled in confusing ways.
“The two main types [of bottled water] are purified and distilled,” says Giammar. “Purified water is simply any water that has gone through the normal treatment processes to make it safe for drinking. Distilled water has been evaporated and re-condensed to remove all the ions from it.” Ions are small-charged atoms or molecules of dissolved elements.
Bottled tap water
Purified water, then, can be simply bottled municipal water, or stated differently, bottled tap water. Often people assume purified water means it’s more pure than tap water, which is not true, says Giammar.
Many bottled waters also claim to be spring water, which “simply means the water originally came from an underground source called an aquifer,” Giammar explains. “This groundwater is generally of a higher quality at the source, as it has already undergone some natural filtration from being underground.”
Many bottled waters are tinkered with for optimum flavor. The most basic difference is that bottled waters usually don’t have the chlorine residual taste that most tap water in the United States has. This is because water bottlers often use other methods for disinfecting the water than the municipal chlorination process.
The most common such methods are ozonation and ultraviolet irradiation, says Giammar. “Ozone, like chlorine, is a good oxidizer and good at killing pathogens.”
UV light also is good to this end. Neither of these methods leaves any residual taste, such as chlorine.
“The only advantages to bottled water would be convenience and aesthetics,” Giammar says. “Convenience, because the water can be brought to you, often cold, in a bottle. Also, some consumers may prefer the taste.”
Besides using different disinfection methods, some bottlers go further in crafting their brands of water, says Giammar.
“Some bottled waters have carefully controlled amounts of ions. In the case of Dasani, for example, they remove all the ions from the water in a process called reverse osmosis, and then they selectively add calcium, magnesium and bicarbonate that was there initially.”
In municipal water there are certain ions that give it some taste, Giammar explains. Most of these ions are perfectly healthy, including calcium ions. Calcium ions, however, are often removed because they create scaling and soap scum on pipes and bathroom fixtures.
Lead, copper concerns
Nevertheless, there is still one very small risk factor to tap water: lead and copper. “The lead and copper rule,” says Giammar, “requires utilities to ensure at various points in the distribution system that these levels are below the standards set, but they of course don’t test every tap in the system.”
If you live in a house with old plumbing, corrosion of the pipes can lead to copper and lead leaching into the water. If you’re concerned about this, Giammar suggests getting a water filter, such as that made by Brita.
“The Brita filter, for example, will have activated carbon and ion exchange resins. The ion exchange can remove some copper and lead as well as a little of the residual chlorine taste.”
Bottled water evades the lead and copper problem as there are no intermediate pipes to worry about.
Even so, Giammar emphasizes the safety of municipal water.
“Our drinking water standards are designed to protect us, so that you would have, in the case of a carcinogen, an incremental cancer risk of one in a million — a common rule of thumb they use for developing these standards.”
In other words, these restrictions on carcinogens mean that there’s about a one in a million chance that drinking this water might cause cancer in your lifetime, a value so low that it’s considered nearly negligible.
“I wouldn’t say that the risk is completely negligible, but rather that it is a value that has been found to be publicly acceptable and far below other cancer-risk behaviors,” Giammar explains. “For example, you can also have an increased cancer risk of one in a million from flying 6,000 miles in an airplane because of cosmic radiation.”
Despite the safety of tap water, Giammar believes that the future of bottled water is bright. The $8.3 billion bottled water industry is growing by 7 to 10 percent each year, according to the Beverage Marketing Corp. research group, which also says American consumers bought more bottled water last year than coffee, milk or beer.
“I think the bottled water industry has established a good niche for themselves,” says Giammar, “and it’s going to be hard for that to die away. There were times, for example, when water, on a per-gallon basis, was more expensive than gas. If we’re willing to spend money and we don’t mind water costing more than gasoline, I think it’s here to stay.”