Trichloroacetic acid

Millis Water Department

Trichloroacetic 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

Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	N/A	0	0	N/A
2015	0.173 ppb	8	2	ND - 0.830 ppb
2016	ND	4	0	ND
2017	0.370 ppb	2	1	ND - 0.740 ppb
2018	0.973 ppb	8	7	ND - 1.50 ppb
2019	0.538 ppb	8	3	ND - 2.27 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.1 ppb

The EWG Health Guideline of 0.1 ppb for trichloroacetic 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.a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

ppb = parts per billion

All test results

Date	Result
2015-02-24	ND
2015-02-24	0.550 ppb
2015-05-27	ND
2015-05-27	ND
2015-08-26	ND
2015-08-26	ND
2015-11-24	ND
2015-11-24	0.830 ppb
2016-02-25	ND
2016-02-25	ND
2016-11-21	ND
2016-11-21	ND
2017-02-21	ND
2017-02-21	0.740 ppb
2018-02-27	1.30 ppb
2018-02-27	ND
2018-05-29	0.510 ppb
2018-05-29	0.670 ppb
2018-08-29	1.40 ppb
2018-08-29	1.30 ppb
2018-11-27	1.50 ppb
2018-11-27	1.10 ppb
2019-02-27	1.26 ppb
2019-02-27	ND
2019-05-30	0.771 ppb
2019-05-30	ND
2019-08-28	ND
2019-08-28	ND
2019-11-26	ND
2019-11-26	2.27 ppb