Chlorate
Southington Water Department
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 | N/A | 0 | 0 | N/A |
2015 | 104.7 ppb | 24 | 18 | ND - 730.0 ppb |
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 |
---|---|---|
2015-03-18 | 99001MR002 | ND |
2015-03-18 | 46034 032015 | ND |
2015-03-18 | 46036 032015 | 100.0 ppb |
2015-03-18 | 46035 035015 | ND |
2015-03-18 | 99001 MR007 | 23.0 ppb |
2015-03-18 | 99001 MR004 | 80.0 ppb |
2015-03-18 | 99001 MR003 | ND |
2015-03-18 | 46039 032015 | ND |
2015-03-19 | 46038 032015 | 730.0 ppb |
2015-03-19 | 46037 042015 | 590.0 ppb |
2015-03-19 | 99001 042015 | ND |
2015-06-25 | 38040 072015 | 130.0 ppb |
2015-06-25 | 23716 072015 | 160.0 ppb |
2015-09-23 | 99001 . 0915 | 57.0 ppb |
2015-09-23 | 99001 _ 0915 | 82.0 ppb |
2015-09-23 | 99001. 0915 | 85.0 ppb |
2015-09-23 | 46036 0915 | 130.0 ppb |
2015-09-23 | 46034 0915 | 97.0 ppb |
2015-09-23 | 46038 0915 | 60.0 ppb |
2015-09-24 | 46035 0915 | 32.0 ppb |
2015-09-24 | 99001 _0915 | 39.0 ppb |
2015-09-24 | 99001_ 0915 | 28.0 ppb |
2015-09-24 | 46037 0915 | 58.0 ppb |
2015-09-24 | 46039 0915 | 32.0 ppb |