Chloroform

Bristol County Water Authority

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

131

Samples

Samples exceeding legal limit (MCL)

108

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	56.2 ppb	22	18	ND - 102.0 ppb
2015	9.66 ppb	5	1	ND - 48.3 ppb
2016	ND	4	0	ND
2017	52.0 ppb	26	22	ND - 78.0 ppb
2018	55.5 ppb	39	35	ND - 85.3 ppb
2019	51.8 ppb	35	32	ND - 75.4 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	Lab ID	Result
2014-01-21	1401190-04_TO12	ND
2014-01-21	1401190-03_TO12	ND
2014-01-21	1401190-02_TO12	ND
2014-02-19	1401528-07_TO02	102.0 ppb
2014-02-19	1401528-08_TO02	89.7 ppb
2014-02-20	1401528-09_TO02	67.0 ppb
2014-02-20	1401528-01_TO02	90.2 ppb
2014-02-20	1401528-02_TO02	83.0 ppb
2014-02-20	1401528-03_TO02	70.0 ppb
2014-02-20	1401528-05_TO02	77.0 ppb
2014-02-20	1401528-06_TO02	90.9 ppb
2014-02-20	1401528-04_TO02	90.4 ppb
2014-03-19	1401911-01_TO02	44.4 ppb
2014-03-19	1401911-02_TO02	61.8 ppb
2014-03-19	1401911-03_TO02	44.4 ppb
2014-03-19	1401911-05_TO02	45.3 ppb
2014-03-19	1401911-06_TO02	59.2 ppb
2014-03-19	1401911-08_TO02	64.4 ppb
2014-03-19	1401911-04_TO02	51.0 ppb
2014-03-20	1401911-07_TO02	63.9 ppb
2014-03-20	1401911-09_TO02	42.2 ppb
2014-09-08	1404927-01_TO12	ND
2015-01-05	1501009-03_TO12	ND
2015-01-05	1501009-02_TO12	ND
2015-01-05	1501009-04_TO12	ND
2015-07-17	1503203-01_TO12	ND
2015-12-30	1512733-01_TO12	48.3 ppb
2016-03-09	1601434-04_TO12	ND
2016-03-09	1601434-03_TO12	ND
2016-03-09	1601434-02_TO12	ND
2016-07-19	1603486-01_TO12	ND
2017-01-31	1701087-04_TO12	ND
2017-01-31	1701087-03_TO12	ND
2017-01-31	1701087-02_TO12	ND
2017-08-15	1708371-01	61.9 ppb
2017-08-15	1708371-02	75.8 ppb
2017-08-15	1708371-04	68.4 ppb
2017-08-15	1708371-06	77.4 ppb
2017-08-15	1708371-07	68.9 ppb
2017-08-15	1708371-08	74.1 ppb
2017-08-15	1708371-09	57.0 ppb
2017-08-15	1708371-10	60.4 ppb
2017-08-16	1708371-11	43.8 ppb
2017-08-16	1708371-03	78.0 ppb
2017-08-16	1708371-05	74.5 ppb
2017-08-16	1703873-02_TO12	ND
2017-11-21	1711644-01	50.9 ppb
2017-11-21	1711644-02	63.4 ppb
2017-11-21	1711644-03	58.6 ppb
2017-11-21	1711644-04	53.8 ppb
2017-11-21	1711644-05	63.5 ppb
2017-11-21	1711644-06	61.0 ppb
2017-11-21	1711644-07	59.1 ppb
2017-11-21	1711644-10	49.6 ppb
2017-11-21	1711644-09	49.3 ppb
2017-11-22	1711644-08	48.9 ppb
2017-11-22	1711644-11	54.1 ppb
2018-01-09	1800842-03_TO12	ND
2018-01-09	1800842-02_TO12	ND
2018-01-09	1800842-01_TO12	ND
2018-02-20	1802398-01	47.4 ppb
2018-02-20	1802398-02	61.4 ppb
2018-02-20	1802398-03	53.1 ppb
2018-02-20	1802398-04	48.9 ppb
2018-02-20	1802398-05	46.5 ppb
2018-02-20	1802398-06	61.1 ppb
2018-02-20	1802398-07	54.8 ppb
2018-02-20	1802398-08	56.5 ppb
2018-02-20	1802398-09	43.9 ppb
2018-02-21	1802398-11	38.9 ppb
2018-02-21	1802398-10	45.3 ppb
2018-05-15	1805423-01	65.9 ppb
2018-05-15	1805423-02	84.1 ppb
2018-05-15	1805423-03	72.6 ppb
2018-05-15	1805423-04	68.3 ppb
2018-05-15	1805423-05	67.1 ppb
2018-05-15	1805423-06	79.9 ppb
2018-05-15	1805423-07	64.6 ppb
2018-05-15	1805423-08	73.0 ppb
2018-08-21	1808574-01	65.7 ppb
2018-08-21	1808574-02	85.3 ppb
2018-08-21	1808575-01	66.5 ppb
2018-08-21	1808575-02	78.5 ppb
2018-08-21	1808575-03	79.3 ppb
2018-08-21	1808575-04	67.6 ppb
2018-08-22	1808575-05	66.6 ppb
2018-08-22	1808575-06	79.7 ppb
2018-08-31	1803935-01_TO12	ND
2018-11-20	1811558-01	52.4 ppb
2018-11-20	1811558-02	54.3 ppb
2018-11-20	1811558-03	56.1 ppb
2018-11-20	1811558-04	52.4 ppb
2018-11-20	1811558-05	49.5 ppb
2018-11-20	1811558-06	63.9 ppb
2018-11-20	1811558-07	51.8 ppb
2018-11-20	1811558-08	63.2 ppb
2019-01-22	1900905-02_TO12	ND
2019-01-22	1900905-03_TO12	ND
2019-01-22	1900905-04_TO12	ND
2019-02-19	1902390-01	43.2 ppb
2019-02-19	1902390-02	59.6 ppb
2019-02-19	1902390-03	53.3 ppb
2019-02-19	1902390-04	73.6 ppb
2019-02-19	1902390-06	57.8 ppb
2019-02-19	1902390-07	52.4 ppb
2019-02-19	1902390-08	47.5 ppb
2019-02-20	1902390-05	43.2 ppb
2019-05-21	1905740-01	53.8 ppb
2019-05-21	1905740-02	52.0 ppb
2019-05-21	1905740-03	64.7 ppb
2019-05-21	1905740-04	56.0 ppb
2019-05-21	1905740-05	58.8 ppb
2019-05-21	1905740-06	69.0 ppb
2019-05-21	1905740-07	70.0 ppb
2019-05-21	1905740-08	70.1 ppb
2019-08-20	19H0643-01	50.9 ppb
2019-08-20	19H0643-02	59.5 ppb
2019-08-20	19H0643-03	67.1 ppb
2019-08-20	19H0643-04	53.3 ppb
2019-08-20	19H0643-05	57.3 ppb
2019-08-20	19H0643-06	75.4 ppb
2019-08-20	19H0643-07	69.0 ppb
2019-08-20	19H0643-08	75.4 ppb
2019-11-19	19K0600-01	41.4 ppb
2019-11-19	19K0600-02	45.0 ppb
2019-11-19	19K0600-03	50.0 ppb
2019-11-19	19K0600-04	44.6 ppb
2019-11-19	19K0600-05	36.9 ppb
2019-11-19	19K0600-06	63.4 ppb
2019-11-19	19K0600-07	52.3 ppb
2019-11-19	19K0600-08	45.5 ppb