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EWG's Tap Water Database — 2021 UPDATE

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Monochloroacetic acid

St. Helena, City Of

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

 

52

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.660 ppb102ND - 3.70 ppb
20150.338 ppb81ND - 2.70 ppb
20160.850 ppb82ND - 3.40 ppb
20170.289 ppb91ND - 2.60 ppb
20182.01 ppb96ND - 3.60 ppb
20191.26 ppb82ND - 6.00 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
2014-02-199590-016-0843ND
2014-02-199590-012-0832ND
2014-02-199590-011-0858ND
2014-02-199590-010-0925ND
2014-06-129590-016-0857ND
2014-06-129590-011-0919ND
2014-08-209590-016-08273.70 ppb
2014-08-209590-011-07572.90 ppb
2014-11-199590-016-0808ND
2014-11-199590-011-0902ND
2015-02-189590-011-08302.70 ppb
2015-02-189590-016-0850ND
2015-05-209590-011-0827ND
2015-05-209590-016-0846ND
2015-08-199590-011-0808ND
2015-08-199590-016-0827ND
2015-11-189590-011-0953ND
2015-11-189590-016-0837ND
2016-02-179590-011-07593.40 ppb
2016-02-179590-016-08163.40 ppb
2016-05-259590-011-0800ND
2016-05-259590-016-0800ND
2016-08-179590-011-0908ND
2016-08-179590-016-0847ND
2016-11-179590-016-0900ND
2016-11-179590-011-0850ND
2017-02-249590-011-0854ND
2017-02-249590-016-0912ND
2017-05-259590-016-10332.60 ppb
2017-05-259590-011-0848ND
2017-08-179590-011-0842ND
2017-08-179590-016-0955ND
2017-11-169590-015-0816ND
2017-11-169590-016-0857ND
2017-11-169590-011-0759ND
2018-02-219590-010-1010ND
2018-02-219590-016-09403.10 ppb
2018-02-229590-011-09153.20 ppb
2018-05-179590-016-10313.60 ppb
2018-05-179590-011-09063.00 ppb
2018-08-149590-016-09362.90 ppb
2018-08-149590-011-08112.30 ppb
2018-11-289590-016-1111ND
2018-11-289590-011-0944ND
2019-02-201610-016-0827ND
2019-02-201610-011-0730ND
2019-05-151610-016-0824ND
2019-05-151610-011-08404.10 ppb
2019-08-221610-016-08206.00 ppb
2019-08-221610-011-0743ND
2019-11-201610-016-0800ND
2019-11-201610-011-0815ND