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EWG's Tap Water Database — 2021 UPDATE

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Monochloroacetic acid

Helena Water System

Monochloroacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

 

96

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20142.43 ppb1612ND - 7.60 ppb
20152.78 ppb1615ND - 5.90 ppb
20161.80 ppb1611ND - 5.50 ppb
20172.01 ppb1612ND - 5.60 ppb
20183.38 ppb1612ND - 8.30 ppb
20191.66 ppb167ND - 5.40 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 53 ppb

The EWG Health Guideline of 53 ppb for monochloroacetic acid was proposed in 2020 by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk.. This health guideline protects against system toxicity.

ppb = parts per billion

All test results

Date Lab ID Result
2014-02-18H14020182-004B1.40 ppb
2014-02-18H14020182-003B1.10 ppb
2014-02-18H14020182-002B1.000 ppb
2014-02-18H14020182-001B1.60 ppb
2014-05-06H14050080-004A6.50 ppb
2014-05-06H14050080-003A6.80 ppb
2014-05-06H14050080-002A7.60 ppb
2014-05-06H14050080-001A6.60 ppb
2014-08-07H14080149-002BND
2014-08-07H14080149-001BND
2014-08-07H14080149-003BND
2014-08-07H14080149-004BND
2014-11-11H14110156-004B2.00 ppb
2014-11-11H14110156-003B1.20 ppb
2014-11-11H14110156-002B1.80 ppb
2014-11-11H14110156-001B1.20 ppb
2015-02-09H15020132-004B3.10 ppb
2015-02-09H15020132-003B2.50 ppb
2015-02-09H15020132-002B2.80 ppb
2015-02-09H15020132-001B2.90 ppb
2015-05-04H15050032-001B5.90 ppb
2015-05-04H15050032-002B5.20 ppb
2015-05-04H15050032-004B5.10 ppb
2015-05-04H15050032-003B1.10 ppb
2015-08-04H15080039-004B1.20 ppb
2015-08-04H15080039-003B1.40 ppb
2015-08-04H15080039-002B1.80 ppb
2015-08-04H15080039-001B1.70 ppb
2015-11-11H15110206-004BND
2015-11-11H15110206-003B4.30 ppb
2015-11-11H15110206-002B1.90 ppb
2015-11-11H15110206-001B3.50 ppb
2016-02-08H16020112-002B1.20 ppb
2016-02-08H16020112-001B1.60 ppb
2016-02-08H16020112-003B1.40 ppb
2016-02-08H16020112-004B2.30 ppb
2016-05-04H16050062-004B2.00 ppb
2016-05-04H16050062-003B4.30 ppb
2016-05-04H16050062-002B5.20 ppb
2016-05-04H16050062-001B5.50 ppb
2016-08-11H16080311-004BND
2016-08-11H16080311-003BND
2016-08-11H16080311-002BND
2016-08-11H16080311-001BND
2016-11-07H16110141-001B1.60 ppb
2016-11-07H16110141-004BND
2016-11-07H16110141-003B2.00 ppb
2016-11-07H16110141-002B1.70 ppb
2017-02-06H17020059-004B2.10 ppb
2017-02-06H17020059-003B2.00 ppb
2017-02-06H17020059-002B2.00 ppb
2017-02-06H17020059-001B2.30 ppb
2017-05-10H17050211-004B5.40 ppb
2017-05-10H17050211-003B5.20 ppb
2017-05-10H17050211-002B3.20 ppb
2017-05-10H17050211-001B5.60 ppb
2017-08-16H17080330-002BND
2017-08-16H17080330-001BND
2017-08-16H17080330-003BND
2017-08-16H17080330-004BND
2017-11-28H17110486-004B1.10 ppb
2017-11-28H17110486-003B0.960 ppb
2017-11-28H17110486-002B0.930 ppb
2017-11-28H17110486-001B1.30 ppb
2018-02-15H18020260-004B3.50 ppb
2018-02-15H18020260-003B3.20 ppb
2018-02-15H18020260-002B3.50 ppb
2018-02-15H18020260-001B4.10 ppb
2018-05-09H18050233-001B7.60 ppb
2018-05-09H18050233-002B8.10 ppb
2018-05-09H18050233-004B8.30 ppb
2018-05-09H18050233-003B6.40 ppb
2018-08-14H18080291-004B5.90 ppb
2018-08-14H18080291-003B1.30 ppb
2018-08-14H18080291-002B1.10 ppb
2018-08-14H18080291-001B1.10 ppb
2018-11-14H18110336-004BND
2018-11-14H18110336-003BND
2018-11-14H18110336-002BND
2018-11-14H18110336-001BND
2019-02-06H19020065-002BND
2019-02-06H19020065-001BND
2019-02-06H19020065-003BND
2019-02-06H19020065-004BND
2019-05-23H19050678-004B5.40 ppb
2019-05-23H19050678-003B4.80 ppb
2019-05-23H19050678-002B4.30 ppb
2019-05-23H19050678-001BND
2019-08-20H19080561-004BND
2019-08-20H19080561-003BND
2019-08-20H19080561-002BND
2019-08-20H19080561-001BND
2019-11-13H19110258-001B3.40 ppb
2019-11-13H19110258-004B1.90 ppb
2019-11-13H19110258-003B2.80 ppb
2019-11-13H19110258-002B3.90 ppb