Cancer-causing chemical in your drinking water?

The Environmental Working Group, a nonprofit advocacy group based in Washington, D.C., would like to see a national standard set below 0.06 parts per billion, says spokesperson Leeann Brown. Scant research has been done in humans to ascertain at what level the chemical becomes harmful, but a Chinese study from 1965 suggests that harmful effects may occur in humans following exposures of 20 parts per million or 20,000 parts per billion, according to the Environmental Protection Agency website.

Right now, no safety standard for hexavalent chromium exists and utility companies don't have to test for the chemical. "There's very little consumers can do to avoid it," Brown adds.

Turning to bottled water would be a foolish move, she says, especially if you live in Boston, which has levels below the proposed safety limit. Bottled water makers, like public utility suppliers, also don't do testing for hexavalent chromium. So it's possible that the pricey bottle of spring water you order in Abe & Louie's has higher chromium levels than what comes out of the restaurant tap.

If you're unhappy ingesting even a tiny amount of hexavalent chromium, you can buy a reverse osmosis filter for your home tap, says Brown, which will filter out the chemical. But expect to spend upwards of $200 plus more to replace the filters. Rest assured, though, that you're probably at minimal health risk from the levels in Massachusetts' tap water and just be happy you don't live in Oklahoma.