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What's in Your Drinking Water?

Everything you need to know in order to fill a glass from your tap with confidence.

Safe drinking water is something we Americans tend to take for granted, until a crisis like lead contamination in Flint, Michigan, makes us wonder what chemicals could be lurking in our own taps.


"What's happened in Flint has definitely made us look closer at other cities—with lead and with other contaminants as well," says Erik Olson, director of NRDC's Health program, whose team has fought to protect drinking water—both locally and nationally—for decades. In fact, Lynn Thorp, national campaigns director for the nonprofit organization Clean Water Action, says NRDC has been the group's most valued partner in efforts to enforce the federal Safe Drinking Water Act. "Together, we've been a watchdog for the public at every stage of implementation and for all the many parts of the law," she says.

While there have been victories over the years, you should still be aware of—and vigilant about—what might be in your pipes, faucets, or local water supply. Here's what you should know and how to stay safe.

It's not just about lead

All public water suppliers in the United States are required to uphold certain levels of water quality. As long as these requirements are met, Olson says, most Americans can drink their local tap water without having to worry. Still, violations do happen. And sensitive groups, like pregnant women and children, are at higher risk for health complications, especially from the following contaminants.

Lead: Likely the most famous bad guy, this heavy metal can leach from lead pipes and plumbing fixtures, especially when the water flowing through them is highly corrosive. It can cause neurological and behavioral problems in children and adverse health effects in adults. "It's a more common problem in cities with older water systems," Olson says, "but what a lot of people don't realize is that even relatively new brass fixtures and faucets can still contain significant amounts of lead. Just because your home is less than 20 years old doesn't necessarily mean you're lead-free"

Perchlorate: This widespread toxic chemical, used in rocket fuel, explosives, and road flares, can interfere with thyroid hormone production. Perchlorate has been detected in the water in at least 26 states, yet, there is no federal drinking-water standard for its presence. In 2011, after more than a decade of pressure from environmental and health groups led by NRDC, the U.S. Environmental Protection Agency announced that it will set such a standard—but its proposed ruling isn't projected until 2017. Tired of waiting, NRDC filed a lawsuit against the EPA in February 2016 for its failure to act in the time frame allotted by the Safe Drinking Water Act.

Atrazine: This endocrine-disrupting chemical is the most commonly detected pesticide in U.S. waters. NRDC studies have found its contamination is most common in drinking water across the Midwest and southern United States. The EPA currently monitors a sample of community water systems to determine if atrazine concentrations pose a risk to public health, but NRDC has called on the government to phase out the use of this chemical entirely.

Pathogens: Bacteria, viruses, and parasites that cause illness can find their way into water supplies that are inadequately treated to kill germs. Fortunately, these pathogens are much better controlled today than they once were. After a 1993 waterborne-disease outbreak in Milwaukee sickened more than 400,000 people, Olson says, "NRDC really led the charge in changing the EPA's rules and safeguards."

Pharmaceuticals: Prescription drugs enter our water supply when patients release traces in their urine or flat-out flush unused medication down the sink or toilet. NRDC has petitioned the FDA to pay more attention to medicines making their way into the environment, and a 2010 NRDC report provided recommendations for reducing the flow of these drugs into our waters.

Chlorine treatment by-products: Chemicals used in drinking water's disinfection process, such as trihalomethanes and haloacetic acids, may cause cancer and reproductive problems if present in high quantities.

Arsenic: The EPA estimated in 2000 that nearly 36 million Americans drank water containing arsenic at or above 3 parts per billion—the level NRDC had urged be established as a drinking water standard. "The EPA had delayed and delayed updating the arsenic standard that was originally issued in the 1960s, but we finally got them to relent and update the arsenic number based on modern science in the early 2000s," Olson says. Since then, arsenic levels across the country have declined as a result, he adds, but the contaminant is still worth looking out for.

What you can do

If you get your drinking water from a public system, start by checking the annual Consumer Confidence Report published by your water supplier. It's usually mailed once a year with your water bill and should also be available online. The report summarizes which contaminants have been found in your drinking water and whether any of them have reached potentially dangerous levels. Your supplier is also required to send out public notifications if any of these levels violate health and safety standards.

If you suspect you have lead pipes or fixtures, if you get your water from a private well, or if you notice a change in your water's taste, color, or clarity, Olson recommends having your water tested for contaminants. Call the Safe Drinking Water Hotline at 800-426-4791 to find a state-certified lab in your area.

A whole-house or at-the-tap water filter might also offer some peace of mind. Choose one that's certified by NSF International to remove the contaminant you're concerned about. (For example, some are certified to remove lead. Some aren't.) And if you're wondering about bottled water, take note: Switching to plastic may be a smart short-term option if you experience a temporary quality problem. But in general, bottled water has been proved to be no safer than regular tap water.

Finally, says Thorp, value what comes out of your tap. "Consumers need to look upstream and find out where we are creating pollution in the first place," she says. "We all need to get behind solutions for preventing contamination when we build our homes, grow our food, and make our energy."

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