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EWG's Tap Water Database — 2019 UPDATE

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Chlorate

City of Kerrville

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.

 

28

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012N/A00N/A
2013ND140ND
2014ND140ND
2015N/A00N/A
2016N/A00N/A
2017N/A00N/A

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 210 ppb

The EWG 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
2013-08-2635106170009AMND
2013-08-2635106170005AMND
2013-08-2635106170011AMND
2013-08-2635106170003AMND
2013-08-2635106170001AMND
2013-08-2635106170007AMND
2013-08-2735106349005AMND
2013-08-2735106349001AMND
2013-08-2735106349009AMND
2013-08-2735106349003AMND
2013-08-2735106349011AMND
2013-08-2735106349007AMND
2013-11-1335115870001AMND
2013-11-1335115870003AMND
2014-02-1835127285007AMND
2014-02-1835127285005AMND
2014-02-1835127285001AMND
2014-02-1835127285011AMND
2014-02-1835127285003AMND
2014-02-1835127285009AMND
2014-02-19EP005 MCND
2014-02-19EP007 MCND
2014-02-19MR004ND
2014-02-19MR002ND
2014-02-19MR003ND
2014-02-19EP003 MCND
2014-05-2035139241003AMND
2014-05-2035139241001AMND