EWG tap water database reveals full list of contaminants in US drinking water supply

By Mary Ellen Shoup contact

- Last updated on GMT

The EWG tap water database details all contaminants both unregulated and regulated by the EPA. ©iStock/mheim3011
The EWG tap water database details all contaminants both unregulated and regulated by the EPA. ©iStock/mheim3011
A new tap water database by EWG (Environmental Working Group) aims to inform Americans about their drinking water and create a higher safety standard for tap water quality based more on scientific input than federal regulations. 

The tap water database aggregated data from 50,000 public water systems from all US states as well as EPA (Environmental Protection Agency) drinking water tests conducted between 2010 and 2015.

Trust in drinking water has waned with two out of three Americans believing their community’s tap water is at risk, according to study conducted by Nestlé Waters North America.

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

“Just because your tap water gets a passing grade from the government doesn’t always mean it’s safe.”

Water utilities provide customers with annual quality reports that compare contaminant levels to regulatory limits, which have been criticized by public and environmental health organization for not being stringent enough and not providing comparisons to other US drinking water systems.

The EWG tap water database provides users with a list of all contaminants, regulated and unregulated, by zip code or local utility’s name.

Instead of comparing the levels of pollutants to the legal limits set by regulatory agencies, EWG’s guide relies on what current science finds are levels that fully protect public health, particular that of infants, children, pregnant women, and other vulnerable populations, the group said.

Contaminants detected

While the vast majority of utilities were found to be in compliance with federal regulatory standards, contaminants were still detected in concentrations exceeding levels that could pose health risks according to scientists.

Water utilities are tested for roughly 500 contaminant and detected 267 in the US drinking water supply. Frequently found contaminants include, Chromium-6 detected in drinking water supplies serving 250m Americans, 1,4-Dioxane in tap water that supply 8.5m people in 27 states, and Nitrate detected in more than 1,800 water systems in 2015.

The data compiled by EWG also found that between 2010 and 2015, almost 19,000 public water systems had at least one detection of lead above 3.8 parts per billion.

In addition, the data results showed that there were 160 additional unregulated contaminants not included on the EPA list of regulated drinking water contaminants.

“It’s time to stop basing environmental regulations on political or economic compromises, and instead listen to what scientists say about the long-term effects of toxic chemicals,”​ Cook said.

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