If you're eating organic but drinking unfiltered tap water, chances are you're missing a major chemical offender. During a recent 2 1/2-year nationwide investigation of treated tap water, the nonprofit Environmental Working Group (EWG) found 260 contaminants. More than half of these remain unregulated by the federal Environmental Protection Agency, despite evidence linking many of them to cancer and other health risks. EWG estimates that water contaminated by these unregulated chemicals serves nearly 200 million people in 42 states.

In the short run, says Alan Greene, MD, FAAP, of Stanford University's Lucile Packard Children's Hospital, "a simple, carbon-based filter will take out a lot of what's problematic." To learn more about what's in your local water, start by checking out the national database at www.ewg.org/sites/tapwater.

In the long run, the state of our water is a great reason to buy organic whenever possible, especially when it comes to lessening runoff from our biggest polluting crops: corn, soy, and cotton.

Sources: Environmental Working Group; Alan Greene, MD, FAAP