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EWG's Tap Water Database — 2019 UPDATE

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Chlorate

Epcor Water - Sun City

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.

 

36

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
20133.86 ppb365ND - 35.0 ppb
2014N/A00N/A
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
2013-02-112777979ND
2013-02-112777998ND
2013-02-112777965ND
2013-02-112777969ND
2013-02-112777974ND
2013-02-112778016ND
2013-02-112777989ND
2013-02-112778007ND
2013-02-122778900ND
2013-02-122778891ND
2013-02-132779624ND
2013-02-13277973231.0 ppb
2013-02-132779602ND
2013-02-132779634ND
2013-02-13277968930.0 ppb
2013-02-13277968235.0 ppb
2013-02-132779595ND
2013-02-132779614ND
2013-08-1223246901ND
2013-08-1223247101ND
2013-08-1223246401ND
2013-08-1223247001ND
2013-08-1223246501ND
2013-08-1223246601ND
2013-08-1323247401ND
2013-08-1323247301ND
2013-08-1323247201ND
2013-08-1323246701ND
2013-08-1323246001ND
2013-08-1323246101ND
2013-08-1423247501ND
2013-08-142324680123.0 ppb
2013-08-142324770120.0 ppb
2013-08-1423246301ND
2013-08-1423246201ND
2013-08-1423247601ND