How Clean Is Your Drinking Water?

A recent analysis of the nation's water supplies reveals some dirty little secrets. Is your city on the Worst Water list?

May 17, 2011

Ever wonder what's in your glass of water—besides water? Unfortunately, the answer may be "plenty." The laws designed to guarantee clean drinking water are getting weaker by the day, and a new report from the advocacy-oriented nonprofit Environmental Working Group (EWG) reveals just how much contaminated drinking water is pumping through our nation's municipal water pipes.

The EWG reviewed 20 million water-quality tests from the past five years, and found that the water flowing to about 85 percent of the population contains 316 contaminants. Of those, 202 chemical contaminants are not regulated by the Environmental Protection Agency, meaning that any water supply can have any level of the pollutants and a municipality doesn't need to take action to remove them. In some cases, those pollutants are at low levels and don't cause harm to human health. In others, however, the problems could be serious. For example, perchlorate, a component of rocket fuel that was recently detected by the Centers for Disease Control and Prevention in nearly all Americans tested, is one of those unregulated chemicals, and it can interfere with the body's thyroid-hormone production, which could lead to metabolic disorders and diabetes.


EWG also used its data to rank cities with the best and worst water supplies, based on the number and concentrations of hazardous chemicals found. At the top of the list were Arlington, Texas; Providence, Rhode Island; Fort Worth, Texas; Charleston, South Carolina; and Boston, Massachusetts. The five worst? Reno, Nevada; Riverside County, California; Las Vegas, Nevada; Riverside (city water supply), California; and Pensacola, Florida.

As growing populations and climate change threaten the availability of clean drinking water, it's important to make sure the water we do have is clean and reliable. Unfortunately, the law that regulates our water, the Safe Drinking Water Act, is decidedly outdated: A recent analysis of drinking-water laws by The New York Times found that not a single contaminant has been added to the act's list of regulated chemicals since 2000. In some cases, where research has found that chemicals can be harmful at lower doses than previously believed, the standards for regulating those chemicals have remained unchanged since 1974 when the law went into affect. And new threats like hydraulic fracturing used in natural-gas drilling use chemicals exempt from regulation and could further pollute our drinking water.

Your best defense against these pollutants is not bottled water, which often comes from those same polluted municipal supplies, but a water filter, provided you get a filter that actually removes the chemicals in your supply. Here's what you need to know:

Know What's In Your Water. "If you're worried about contaminants, do your research to know what contaminants you need to be worried about, if any," says Rick Andrew, operations manager of the Drinking Water Treatment Unit Program at NSF, an independent agency that tests water filters and certifies contaminant-removal claims by manufacturers. The new EWG database is an easy-to-use tool that will tell you what specific pollutants are in your water. A more accurate tool, which gives you the actual levels of those pollutants, is a Consumer Confidence Report, an annual report that all municipal water suppliers are required to publish and provide free to the public. Like most government documents, however, those can be hard to read and interpret. So a final alternative is to have your home's water tested. Many cities will do this for free, says Andrew, adding that these are great ways of finding out if you have lead in your pipes—something that a Consumer Confidence Report can't tell you. If your city doesn't provide free tests, you can pay an independent lab to do it for you. Andrews suggests finding one that's certified by your state; the U.S. Environmental Protection Agency maintains a list of state-certified labs.

Find A Filter. Water filters come in a dizzying array of styles and types. Carbon filters come in pitcher-style, faucet mounts, countertop, and under-the-sink varieties, and sometimes carbon filters are combined with ceramic filters or reverse-osmosis filters to remove a wider variety of pollutants. You can get drinking-water only filters or whole-house units that filter all the water used for drinking, showering, and washing your clothes. There isn't one "silver bullet" style that will take all the junk out of all water—all the more reason to do your research before buying. NSF maintains a searchable database for its certified filters and the contaminants they remove at When you're filter shopping, don't just consider up-front costs, says Andrew. Look at other factors like the ease of installation—"You may have to cut a whole in a countertop to put in a faucet," he says—how expensive the replacement filters cost, and how often you need to replace them.

Read The Fine Print. "Different products have different capabilities in terms of which contaminants they remove," says Andrew. "The [water filter] industry has done some surveys over the years, and they've found that in general, most people are buying a filter because they want the taste and appearance of the water to be better, not because of specific contaminant concerns." As a result, some of the most basic pitcher-style filters are certified to do just that—remove chlorine and off-tastes and improve appearance—but not much else. Any filter you do purchase should be NSF-certified, but read the fine print to find out exactly what it's certified to remove.

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