The Environmental Working Group has released its National Tap Water Database – a project two years in the making that allows nearly every American to punch in their zipcode to find out exactly what’s in their local drinking water and how it can affect their health.

The information in the database goes far beyond anything utilities or the Environmental Protection Agency provides. EWG found a number of contaminants, that while regulated under the Safe Drinking Water Act, are often found at levels that many scientists believe pose health risks.

“Americans deserve the fullest picture possible of what’s in their tap water,” said EWG President Ken Cook. “But they won’t get that information from the government or, in many cases, from their utilities.”

The database includes data from almost 50,000 public water systems in all 50 states and the District of Columbia.

By entering their zip code or local utility’s name, users will find all contaminants detected in tests by the utilities themselves and reported to federal or state authorities. Instead of comparing the levels of pollutants to the legal limits set by regulatory agencies, EWG’s guide relies on what the best and most current science considers to be levels that will protect public health, especially that of infants, children, pregnant women and other vulnerable populations.

The vast majority of utilities are in compliance with federal regulations, but their water still often contains contaminants in concentrations exceeding the levels that scientists say pose health risks. Many of the existing legal limits are set far above levels that are truly health protective.

Because the Environmental Protection Agency has not added a new chemical to the list of regulated contaminants in 20 years, more than half of the contaminants detected in U.S. tap water had no regulatory limit at all, meaning they could legally be present at any concentration and that utilities don’t have to test for them or tell their customers about them.

EWG last published a national drinking water report in 2009. Along with the Tap Water Database, EWG also provides a list of filter systems that can significantly reduce the contaminant levels in their water.