Chloroform

Sandwich Water District

Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Read More.

In addition to tap water disinfection, chloroform pollution in the environment also comes from industrial discharges from pulp and paper mills, and from urban wastewater effluent. Human studies show that chloroform damages the kidneys, liver and central nervous system. In animals, chloroform causes infertility, birth defects and cancer.

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	1.19 ppb	18	18	0.580 ppb - 2.10 ppb
2015	1.14 ppb	11	11	0.620 ppb - 1.60 ppb
2016	1.20 ppb	18	18	0.630 ppb - 2.10 ppb
2017	1.37 ppb	13	13	0.570 ppb - 2.20 ppb
2018	1.03 ppb	18	17	ND - 1.98 ppb
2019	1.03 ppb	16	16	0.540 ppb - 1.85 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.4 ppb

The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as 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
2014-01-07	0.580 ppb
2014-01-07	1.80 ppb
2014-01-07	1.80 ppb
2014-04-15	0.850 ppb
2014-04-15	0.670 ppb
2014-04-15	1.90 ppb
2014-04-15	0.580 ppb
2014-04-15	1.20 ppb
2014-04-15	0.880 ppb
2014-04-15	0.720 ppb
2014-04-15	1.30 ppb
2014-04-28	0.770 ppb
2014-07-25	1.20 ppb
2014-07-25	2.10 ppb
2014-07-25	0.750 ppb
2014-10-15	1.20 ppb
2014-10-15	1.30 ppb
2014-10-15	1.80 ppb
2015-02-26	1.60 ppb
2015-02-26	1.10 ppb
2015-04-06	1.000 ppb
2015-04-06	0.790 ppb
2015-04-06	1.50 ppb
2015-04-06	1.50 ppb
2015-04-06	0.700 ppb
2015-04-07	0.620 ppb
2015-07-17	1.10 ppb
2015-07-17	0.980 ppb
2015-07-17	1.60 ppb
2016-01-19	1.000 ppb
2016-01-19	1.20 ppb
2016-01-19	1.000 ppb
2016-02-16	1.000 ppb
2016-02-16	1.30 ppb
2016-02-16	1.40 ppb
2016-06-09	0.630 ppb
2016-06-09	1.60 ppb
2016-06-09	0.690 ppb
2016-06-09	1.10 ppb
2016-06-09	0.840 ppb
2016-06-09	2.10 ppb
2016-09-20	1.30 ppb
2016-09-20	0.820 ppb
2016-09-20	1.50 ppb
2016-12-07	1.70 ppb
2016-12-07	0.870 ppb
2016-12-07	1.50 ppb
2017-03-01	2.20 ppb
2017-03-01	1.50 ppb
2017-05-08	1.000 ppb
2017-05-08	1.50 ppb
2017-05-08	1.80 ppb
2017-05-08	2.00 ppb
2017-05-08	0.790 ppb
2017-05-09	0.650 ppb
2017-05-09	1.20 ppb
2017-05-09	0.570 ppb
2017-12-13	1.33 ppb
2017-12-13	1.71 ppb
2017-12-13	1.51 ppb
2018-01-22	1.47 ppb
2018-01-22	1.98 ppb
2018-01-22	1.04 ppb
2018-05-02	0.610 ppb
2018-05-02	0.640 ppb
2018-05-02	1.23 ppb
2018-05-02	1.26 ppb
2018-05-02	1.13 ppb
2018-05-02	ND
2018-05-07	0.630 ppb
2018-05-07	0.690 ppb
2018-05-07	0.580 ppb
2018-07-16	0.950 ppb
2018-07-16	1.48 ppb
2018-07-16	1.06 ppb
2018-10-03	1.25 ppb
2018-10-03	1.47 ppb
2018-10-03	1.08 ppb
2019-02-13	0.820 ppb
2019-02-13	1.55 ppb
2019-02-13	1.05 ppb
2019-05-22	0.700 ppb
2019-05-23	1.30 ppb
2019-05-23	0.670 ppb
2019-05-23	1.09 ppb
2019-05-23	0.870 ppb
2019-05-23	0.540 ppb
2019-05-23	1.10 ppb
2019-05-23	0.550 ppb
2019-07-22	1.12 ppb
2019-07-22	0.770 ppb
2019-07-22	1.37 ppb
2019-12-03	1.85 ppb
2019-12-03	1.17 ppb