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How to Know If Your Drinking Water Is Safe From Harmful Chemicals

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Many drinking water systems across the U.S. contain contaminants that may pose health risks. Anne-Christine Poujoulat/AFP/Getty

The Environmental Working Group (EWG) has just released a new online tool that allows users to check the safety of drinking water where they live. With just a ZIP code, the database delivers information about the contaminants found in the water utility serving that region. Release of the tool is accompanied by a guidebook and a compelling summary of the state of drinking water in America. 

Investigations by the nonprofit EWG found that many water systems are delivering industrial and agricultural contaminants with each glass of tap water. But whether the amounts of these chemicals are reason for concern is a matter of debate. Levels considered safe by federal and state regulatory authorities are not always supported by the scientific data on health risks. 

To assess the state of drinking water throughout the country, the EWG obtained data from state agencies and the Environmental Protection Agency for testing conducted fr0m 2010 to 2015. A total of 48,172 utilities from all 50 states were included in the study. 

The EWG analysis uncovered 267 contaminants out of the 500 tested. The chemicals included 93 that the EWG says are linked to an increased risk of cancer, 78 that have been tied to brain and nervous system damage, 63 associated with developmental harm to children and fetuses, and dozens of others that may be implicated in fertility or hormonal problems. The levels of the contaminants are not necessarily high enough to cause any of this damage, and many of these links are not proven as causative.

But there is reason to be concerned. As is widely known, high levels of lead in the drinking water reaching residents of Flint, Michigan, have caused a widespread and long-lasting crisis. Lead is unsafe at any level. According to the EWG, nearly 19,000 public water systems contained lead exceeding 3.8 parts per billion, which is considered risky for formula-fed babies. 

Some of the lesser-known dangers found in the tested water include the industrial chemical chromium-6; 1,4-dioxane, an industrial solvent and by-product of some detergents and shampoos; and nitrates, which are used in agricultural fertilizers. 

The EWG also found a correlation between income levels and water quality. Areas with a higher average income often had fewer contaminants than lower-income areas. The East Los Angeles Water District had the highest number of contaminants of all the regions tested. This area serves 115,000 people and has a median income that is 20 percent below the national average. 

For anyone wishing to find out how their region fares when it comes to drinking water safety, enter a ZIP code here

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