What Is in Tap Water?
We drink water to stay hydrated and flush out toxins. But could tap water actually be exposing us to more potentially harmful chemicals? Perhaps. A 2009 analysis by the Environmental Working Group found a whopping 315 pollutants in U.S. tap water, including arsenic (a heavy metal) and pesticides. More than half of the compounds are not regulated by the EPA, which means they can legally be present in tap water in any amount.
For instance, perchlorate—a currently unregulated chemical that's used to make rocket fuel, flares and explosives—contaminates the drinking water of up to 26 million Americans. The chemical has been shown to reduce thyroid hormone production; experts worry about the risks it poses particularly to babies and children. "Potentially even a very mild degree of low thyroid function could have an adverse effect on cognitive outcomes for a fetus. However, no studies to date have shown effects of low-level perchlorate exposure on thyroid function in pregnant women," says Elizabeth Pearce, M.D., an endocrinologist at the Boston University School of Medicine.
In December 2010, the Environmental Working Group also reported finding hexavalent chromium (chromium-6), the "Erin Brockovich" contaminant that the EPA considers "likely to be carcinogenic to humans," in the drinking water of 31 U.S. cities, including Chicago and Los Angeles. In the wake of this report, the EPA is reassessing the "oral reference dose" (or upper limit of what is considered safe), with a final ruling expected by the end of the year.
What You Can Do for Better Water
Have your water tested—especially if your water comes from a private well or you live near a plant that might use perchlorate or in an area, like parts of California, where chromium-6 is a known a problem, says Pauli Undesser, M.S., director of regulatory and technical affairs of the Water Quality Association. In fact, says Undesser, it's a good idea for everyone to test their tap water. (Call the EPA's Safe Water Hotline: 800-426-4791 to locate a laboratory. Cost starts around $20.)
Once you know what's in your water—mercury, lead from piping or even pesticides—you can choose a filter certified by NSF International or the Water Quality Association to screen specific contaminants. Often, a $20 carbon-based Brita pitcher with a filter will do the trick. Don't assume that bottled water is better: per the FDA, it must meet the same standards as tap.