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EWG's Tap Water Database

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Chlorate

Beauregard Water Works District #3

Chlorate forms in drinking water as a byproduct of disinfection. Chlorate impairs thyroid function, making chlorate exposure most harmful during pregnancy and childhood. Read More.

In 2002, California scientists proposed an advisory value, called an action level, for chlorate at 200 parts per billion. Between 2013 and 2015, the EPA collected data through the Unregulated Contaminant Monitoring Rule program and found that over 15 percent of water tests from 38 percent of utilities had chlorate levels above a health-protective concentration, which federal scientists defined as 210 parts per billion, nearly equivalent to the California advisory value.

Click here to read more about disinfection byproducts.

 

24

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2010N/A00N/A
2011N/A00N/A
2012N/A00N/A
2013N/A00N/A
2014N/A00N/A
2015ND240ND

ppb = parts per billion.

State and national drinking water standards and health guidelines

Health Guideline 210 ppb

The health guideline of 210 ppb for chlorate was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against hormone disruption.

ppb = parts per billion.

All test results

Date Lab ID Result
2015-02-273197606ND
2015-02-273197683ND
2015-02-273197621ND
2015-02-273197574ND
2015-02-273197598ND
2015-02-273197640ND
2015-02-273197691ND
2015-02-273197562ND
2015-02-273197588ND
2015-02-273197674ND
2015-03-113205156ND
2015-03-113205164ND
2015-08-183305571ND
2015-08-183305550ND
2015-08-183305962ND
2015-08-183305511ND
2015-08-183305614ND
2015-08-183305546ND
2015-08-183305590ND
2015-08-183305602ND
2015-08-183305529ND
2015-08-183305580ND
2015-08-183305952ND
2015-08-183305538ND