Know Your Environment. Protect Your Health.

Chlorate

City of Nampa

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.

 

34

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20142.01 ppb343ND - 26.5 ppb
2015N/A00N/A
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
2014-01-30WA97-SE1-14-02170-5440ND
2014-01-30WA97-SE1-14-02170-5445ND
2014-01-30WA97-SE1-14-02170-5435ND
2014-01-30WA97-SE1-14-02170-5437ND
2014-01-30WA97-SE1-14-02170-5436ND
2014-01-30WA97-SE1-14-02170-5430ND
2014-01-30WA97-SE1-14-02170-542926.5 ppb
2014-01-30WA97-SE1-14-02170-543121.8 ppb
2014-01-30WA97-SE1-14-02170-5432ND
2014-01-30WA97-SE1-14-02170-5434ND
2014-01-30WA97-SE1-14-02170-5433ND
2014-01-30WA97-SE1-14-02170-5443ND
2014-01-30WA97-SE1-14-02170-5442ND
2014-01-30WA97-SE1-14-02170-5444ND
2014-01-30WA97-SE1-14-02170-5441ND
2014-01-30WA97-SE1-14-02170-5438ND
2014-01-30WA97-SE1-14-02170-5439ND
2014-07-21WA97-SE2-14-13959-32542ND
2014-07-21WA97-SE2-14-13959-32545ND
2014-07-21WA97-SE2-14-13959-32538ND
2014-07-21WA97-SE2-14-13959-32543ND
2014-07-21WA97-SE2-14-13959-32537ND
2014-07-21WA97-SE2-14-13959-32539ND
2014-07-21WA97-SE2-14-13959-32540ND
2014-07-21WA97-SE2-14-13959-32541ND
2014-07-21WA97-SE2-14-13959-32546ND
2014-07-21WA97-SE2-14-13959-32532ND
2014-07-21WA97-SE2-14-13959-3253320.0 ppb
2014-07-21WA97-SE2-14-13959-32531ND
2014-07-21WA97-SE2-14-13959-32536ND
2014-07-21WA97-SE2-14-13959-32547ND
2014-07-21WA97-SE2-14-13959-32544ND
2014-07-21WA97-SE2-14-13959-32535ND
2014-07-22WA97-SE2-14-13959-32534ND