Know Your Environment. Protect Your Health.

Chlorate

Modern Electric Water Company

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.

 

27

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND140ND
20151.92 ppb131ND - 25.0 ppb
2016N/A00N/A
2017N/A00N/A
2018N/A00N/A
2019N/A00N/A
2020N/A00N/A
2021N/A00N/A
2022N/A00N/A
2023N/A00N/A

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

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
2014-05-30WA97-SE1-14-10653-25560ND
2014-05-30WA97-SE1-14-10653-25562ND
2014-05-30WA97-SE1-14-10653-25559ND
2014-05-30WA97-SE1-14-10653-25561ND
2014-10-13WA97-SE1-14-20788-47041ND
2014-10-13WA97-SE1-14-20788-47042ND
2014-10-13WA97-SE1-14-20788-47047ND
2014-10-13WA97-SE1-14-20788-47046ND
2014-10-13WA97-SE1-14-20788-47045ND
2014-10-13WA97-SE1-14-20788-47044ND
2014-10-13WA97-SE1-14-20788-47048ND
2014-10-13WA97-SE1-14-20788-47043ND
2014-10-13WA97-SE1-14-20788-47039ND
2014-10-13WA97-SE1-14-20788-47040ND
2015-01-12WA97-SE2-15-01353-3194ND
2015-01-12WA97-SE2-15-01353-3195ND
2015-01-12WA97-SE2-15-01353-3192ND
2015-01-12WA97-SE2-15-01353-3193ND
2015-09-14WA97-SE2-15-20060-44654ND
2015-09-14WA97-SE2-15-20060-44657ND
2015-09-14WA97-SE2-15-20060-44658ND
2015-09-14WA97-SE2-15-20060-44655ND
2015-09-14WA97-SE2-15-20060-44649ND
2015-09-14WA97-SE2-15-20060-4465025.0 ppb
2015-09-14WA97-SE2-15-20060-44651ND
2015-09-14WA97-SE2-15-20060-44652ND
2015-09-14WA97-SE2-15-20060-44653ND