So what's in your water? The Environmental Working Group knows: Drinking water may have a lot more in it than just H20 and fluoride, according to an environmental group's analysis of records in 42 states. A survey by the Environmental Working Group released on Tuesday found 141 unregulated chemicals and an additional 119 for which the Environmental Protection Agency has set health-based limits. Most common among the chemicals found were disinfection byproducts, nitrates, chloroform, barium, arsenic and copper. The research-and-advocacy organization compiled findings from the states that agreed to provide data they collected from 1998 to 2003. That data comes from nearly 40,000 water utilities, serving 231 million people. The utilities were required by federal law to report that data to consumers. Even worse: for many of these chemicals ,we just don't begin to know how dangerous they are to human health: For the unregulated chemicals, EPA is still identifying and considering the potential risks for possible future regulations. Nineteen of those chemicals exceeded EPA's unenforced safety guidelines for tap water systems serving at least 10,000 people, according to the advocacy group. . . . Jane Houlihan, EWG's vice president for research, said the group's findings show that the United States allows millions of people to be exposed to some chemicals for which EPA either has never considered the risks or if it has, has no enforceable limits. "So in many communities the water that comes out of the tap could be contaminated with scores of chemicals. People shouldn't be alarmed, but they should be concerned. Our system of public health protections isn't working in this case," Houlihan said. Check it out for yourself: Public Data Show Chemicals in Tap Water