Menu

EWG's Tap Water Database — 2019 UPDATE

Donate

Chlorate

Jefferson County PWSD 3

NOTE: Jefferson County PWSD 3 purchases water from Missouri American St. Louis County & St. Charles County which is required to test for chlorate. Sample information shown below was taken by Missouri American St. Louis County & St. Charles County.

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.

 

88

Samples

0

Samples exceeding legal limit (MCL)

25

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012125.0 ppb8880.0 ppb - 220.0 ppb
2013258.5 ppb88183.0 ppb - 399.0 ppb
2014241.6 ppb88172.0 ppb - 326.0 ppb
2015260.0 ppb88170.0 ppb - 590.0 ppb
2016180.0 ppb88150.0 ppb - 280.0 ppb
2017183.8 ppb88150.0 ppb - 240.0 ppb

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

NOTE: Jefferson County PWSD 3 purchases water from Missouri American St. Louis County & St. Charles County which is required to test for chlorate. Sample information shown below was taken by Missouri American St. Louis County & St. Charles County.

Date Lab ID Result
2012-01-051559510190.0 ppb
2012-01-0515825101120.0 ppb
2012-04-161611350180.0 ppb
2012-04-1616115401120.0 ppb
2012-07-1116992301220.0 ppb
2012-07-111713150190.0 ppb
2012-10-091989350190.0 ppb
2012-10-0919892601190.0 ppb
2013-01-0920587801240.0 ppb
2013-01-0920588201110.0 ppb
2013-02-0521020101ND
2013-02-0521019901ND
2013-02-0521018301ND
2013-02-0521018101ND
2013-02-0621089101210.0 ppb
2013-02-0621019501ND
2013-02-0621019301ND
2013-02-0621017401120.0 ppb
2013-02-062101700190.0 ppb
2013-02-0621016401230.0 ppb
2013-04-0221490501350.0 ppb
2013-04-0321491401130.0 ppb
2013-05-0921800401ND
2013-05-0921800601ND
2013-05-0921801001ND
2013-05-0921801201ND
2013-05-0921799401ND
2013-05-0921799201ND
2013-05-0921798501290.0 ppb
2013-05-0921798101190.0 ppb
2013-05-0921797501260.0 ppb
2013-05-0921797001240.0 ppb
2013-07-1022566101310.0 ppb
2013-07-1022565401310.0 ppb
2013-08-0823174601ND
2013-08-0823174401ND
2013-08-0823174001ND
2013-08-0823173801ND
2013-08-0823172801ND
2013-08-0823172601ND
2013-08-0823171901340.0 ppb
2013-08-0823171501360.0 ppb
2013-08-0823170901320.0 ppb
2013-08-0823170501370.0 ppb
2013-10-0823639601180.0 ppb
2013-10-0823639101200.0 ppb
2013-11-0523934701ND
2013-11-0523934501ND
2013-11-0523933501ND
2013-11-0523933301ND
2013-11-0523932201120.0 ppb
2013-11-0523931601150.0 ppb
2013-11-0523931101190.0 ppb
2013-11-0623932601160.0 ppb
2013-11-0623935101ND
2013-11-0623935301ND
2014-01-1524591601170.0 ppb
2014-01-1524591201160.0 ppb
2014-04-1625141201220.0 ppb
2014-04-1625142101190.0 ppb
2014-07-2326142801230.0 ppb
2014-07-2326143501280.0 ppb
2014-10-0927160001420.0 ppb
2014-10-0927159501290.0 ppb
2015-01-0727907901180.0 ppb
2015-01-0727908301220.0 ppb
2015-04-2228625401180.0 ppb
2015-04-2228624501240.0 ppb
2015-07-1629461701590.0 ppb
2015-07-1629462501320.0 ppb
2015-10-3030801001170.0 ppb
2015-10-3030801101180.0 ppb
2016-01-1130935601170.0 ppb
2016-01-1130935101150.0 ppb
2016-04-0531776101180.0 ppb
2016-04-0531777101160.0 ppb
2016-07-0632597401280.0 ppb
2016-07-0632596601190.0 ppb
2016-10-0533411601160.0 ppb
2016-10-0533412201150.0 ppb
2017-01-1134320601190.0 ppb
2017-01-1234320101150.0 ppb
2017-04-1935120601160.0 ppb
2017-04-1935119601230.0 ppb
2017-07-1436142101150.0 ppb
2017-07-1436142801180.0 ppb
2017-10-1737228001240.0 ppb
2017-10-1737228501170.0 ppb