Know Your Environment. Protect Your Health.

Chlorate

City of Coeur D Alene

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.

 

40

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20148.67 ppb186ND - 37.0 ppb
20153.00 ppb223ND - 26.0 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
2014-08-25WA97-SE2-14-17482-39964ND
2014-08-25WA97-SE2-14-17482-39965ND
2014-08-25WA97-SE2-14-17482-39966ND
2014-08-25WA97-SE2-14-17482-39973ND
2014-08-25WA97-SE2-14-17482-39977ND
2014-08-25WA97-SE2-14-17482-3996937.0 ppb
2014-08-25WA97-SE2-14-17482-3997020.0 ppb
2014-08-25WA97-SE2-14-17482-39972ND
2014-08-25WA97-SE2-14-17482-39974ND
2014-08-25WA97-SE2-14-17482-39976ND
2014-08-25WA97-SE2-14-17482-3997520.0 ppb
2014-08-25WA97-SE2-14-17482-3997122.0 ppb
2014-08-25WA97-SE2-14-17482-3996730.0 ppb
2014-08-25WA97-SE2-14-17482-39968ND
2014-08-28WA97-SE2-14-17482-39960ND
2014-08-28WA97-SE2-14-17482-39963ND
2014-08-28WA97-SE2-14-17482-39961ND
2014-08-28WA97-SE2-14-17482-3996227.0 ppb
2015-01-20WA97-SE2-15-01476-3548ND
2015-01-20WA97-SE1-15-01477-3550ND
2015-01-20WA97-SE1-15-01477-3551ND
2015-01-20WA97-SE2-15-01476-3549ND
2015-06-08WA97-SE2-15-12132-2747220.0 ppb
2015-06-08WA97-SE2-15-12132-27471ND
2015-06-08WA97-SE2-15-12132-27475ND
2015-06-08WA97-SE2-15-12132-27469ND
2015-06-08WA97-SE2-15-12132-27462ND
2015-06-08WA97-SE2-15-12132-27460ND
2015-06-08WA97-SE2-15-12132-27463ND
2015-06-09WA97-SE2-15-12132-27467ND
2015-06-09WA97-SE2-15-12132-27465ND
2015-06-09WA97-SE2-15-12132-27466ND
2015-06-09WA97-SE2-15-12132-27464ND
2015-06-09WA97-SE2-15-12132-2746826.0 ppb
2015-06-09WA97-SE2-15-12132-27470ND
2015-06-09WA97-SE2-15-12132-27459ND
2015-06-09WA97-SE2-15-12132-27461ND
2015-06-09WA97-SE2-15-12132-27476ND
2015-06-09WA97-SE2-15-12132-27474ND
2015-06-09WA97-SE2-15-12132-2747320.0 ppb