Chlorate
Glen Cove 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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2013 | 72.0 ppb | 7 | 7 | 27.0 ppb - 86.0 ppb |
2014 | 134.9 ppb | 7 | 7 | 24.0 ppb - 170.0 ppb |
2015 | N/A | 0 | 0 | N/A |
2016 | N/A | 0 | 0 | N/A |
2017 | N/A | 0 | 0 | N/A |
2018 | N/A | 0 | 0 | N/A |
2019 | N/A | 0 | 0 | N/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 |
---|---|---|
2013-12-16 | DPBMAX1 | 79.0 ppb |
2013-12-16 | DBPMAX2 (44881) | 81.0 ppb |
2013-12-16 | DBPMAX4 (44881) | 86.0 ppb |
2013-12-16 | DBPMAX3 (44881) | 79.0 ppb |
2013-12-16 | 90004 (N09210) | 73.0 ppb |
2013-12-16 | 90001 (EP001) | 27.0 ppb |
2013-12-26 | 90003 N05262 | 79.0 ppb |
2014-06-24 | 44881 MAX4 06201 | 140.0 ppb |
2014-06-24 | 44881 MAX3 06201 | 150.0 ppb |
2014-06-24 | 44881 MAX2 06201 | 160.0 ppb |
2014-06-24 | 44881 062014 | 140.0 ppb |
2014-06-24 | 90003 062014 | 170.0 ppb |
2014-06-26 | 90004 N09210 062 | 160.0 ppb |
2014-06-26 | 90001 EP001 0620 | 24.0 ppb |