Chlorate
Plainview WD
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 |
---|---|---|---|---|
2014 | 5.60 ppb | 15 | 2 | ND - 63.0 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 |
---|---|---|
2014-05-13 | UCMR3 SRN10929 | ND |
2014-05-13 | UCMR3 SRN10927 | ND |
2014-05-13 | UCMR3 SRN10930 | ND |
2014-05-13 | UCMR3 SRN06580 | ND |
2014-05-14 | UCMR3 SRN4095A | ND |
2014-05-14 | UCMR3 SRN10840 | ND |
2014-05-15 | 47122 052014 | ND |
2014-05-30 | 34294 052014 | ND |
2014-11-05 | 04095 112014 | 63.0 ppb |
2014-11-05 | 96580 112014 | ND |
2014-11-12 | 47122 112014 | ND |
2014-11-12 | 10930 112014 | 21.0 ppb |
2014-11-12 | 10927 112014 | ND |
2014-11-12 | 10840 112014 | ND |
2014-11-13 | 10929 112014 | ND |