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 www.nsf.org/Certified/dwtu. 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.
This article orginally appeared on Rodale.com.