Chloroform

Falmouth Water Department

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

194

Samples

Samples exceeding legal limit (MCL)

179

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2013	N/A	0	0	N/A
2014	2.62 ppb	6	6	0.780 ppb - 10.4 ppb
2015	18.8 ppb	23	23	0.730 ppb - 67.1 ppb
2016	16.8 ppb	49	45	ND - 74.8 ppb
2017	15.1 ppb	38	37	ND - 62.2 ppb
2018	4.13 ppb	40	34	ND - 12.6 ppb
2019	4.00 ppb	38	34	ND - 14.0 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
2014-01-14	1.05 ppb
2014-01-14	10.4 ppb
2014-04-03	0.780 ppb
2014-07-10	1.26 ppb
2014-07-10	1.27 ppb
2014-10-08	0.940 ppb
2015-01-13	0.850 ppb
2015-01-13	4.14 ppb
2015-04-02	0.820 ppb
2015-07-07	0.890 ppb
2015-07-07	0.890 ppb
2015-08-20	1.02 ppb
2015-09-03	3.69 ppb
2015-09-03	29.0 ppb
2015-09-03	57.1 ppb
2015-09-03	43.9 ppb
2015-09-03	24.2 ppb
2015-09-03	12.8 ppb
2015-09-03	31.1 ppb
2015-09-03	15.8 ppb
2015-10-15	0.730 ppb
2015-12-03	3.46 ppb
2015-12-03	10.8 ppb
2015-12-03	67.1 ppb
2015-12-03	62.3 ppb
2015-12-03	22.2 ppb
2015-12-03	9.11 ppb
2015-12-03	2.28 ppb
2015-12-03	28.8 ppb
2016-01-11	0.760 ppb
2016-01-11	9.84 ppb
2016-01-12	ND
2016-01-26	ND
2016-01-27	ND
2016-01-27	7.32 ppb
2016-01-28	6.76 ppb
2016-02-04	8.03 ppb
2016-02-05	7.74 ppb
2016-02-08	10.00 ppb
2016-02-09	6.31 ppb
2016-02-10	19.7 ppb
2016-03-02	1.55 ppb
2016-03-02	6.08 ppb
2016-03-02	69.1 ppb
2016-03-02	34.1 ppb
2016-03-02	21.0 ppb
2016-03-02	13.4 ppb
2016-03-02	4.59 ppb
2016-03-02	18.6 ppb
2016-04-11	5.43 ppb
2016-04-11	0.600 ppb
2016-05-20	ND
2016-06-02	3.53 ppb
2016-06-02	15.3 ppb
2016-06-02	52.4 ppb
2016-06-02	31.8 ppb
2016-06-02	14.1 ppb
2016-06-02	16.7 ppb
2016-06-02	19.5 ppb
2016-06-02	10.8 ppb
2016-07-18	0.840 ppb
2016-09-01	12.3 ppb
2016-09-01	42.0 ppb
2016-09-01	54.6 ppb
2016-09-01	47.6 ppb
2016-09-01	29.7 ppb
2016-09-01	15.5 ppb
2016-09-01	74.8 ppb
2016-09-01	16.6 ppb
2016-10-04	0.760 ppb
2016-12-05	2.47 ppb
2016-12-05	4.98 ppb
2016-12-05	40.6 ppb
2016-12-05	17.4 ppb
2016-12-05	20.5 ppb
2016-12-05	8.14 ppb
2016-12-05	3.81 ppb
2016-12-05	16.0 ppb
2017-01-04	0.710 ppb
2017-01-04	3.62 ppb
2017-03-06	2.35 ppb
2017-03-06	5.84 ppb
2017-03-06	33.0 ppb
2017-03-06	33.3 ppb
2017-03-06	8.21 ppb
2017-03-06	4.07 ppb
2017-03-06	5.39 ppb
2017-03-06	8.75 ppb
2017-04-06	1.27 ppb
2017-04-06	0.550 ppb
2017-05-12	2.24 ppb
2017-06-05	14.3 ppb
2017-06-05	7.02 ppb
2017-06-05	62.2 ppb
2017-06-05	36.6 ppb
2017-06-05	26.9 ppb
2017-06-05	20.7 ppb
2017-06-05	28.0 ppb
2017-06-05	10.1 ppb
2017-09-05	13.6 ppb
2017-09-05	27.1 ppb
2017-09-05	47.0 ppb
2017-09-05	31.0 ppb
2017-09-05	18.3 ppb
2017-09-05	15.5 ppb
2017-09-05	27.8 ppb
2017-09-05	13.5 ppb
2017-10-24	ND
2017-12-04	3.01 ppb
2017-12-04	3.36 ppb
2017-12-04	12.4 ppb
2017-12-04	16.7 ppb
2017-12-04	9.83 ppb
2017-12-04	1.43 ppb
2017-12-04	2.45 ppb
2017-12-04	15.1 ppb
2018-01-08	ND
2018-03-05	1.44 ppb
2018-03-05	1.60 ppb
2018-03-05	4.03 ppb
2018-03-05	8.72 ppb
2018-03-05	2.35 ppb
2018-03-05	ND
2018-03-05	ND
2018-03-05	7.66 ppb
2018-04-10	0.660 ppb
2018-04-10	ND
2018-04-17	ND
2018-06-04	3.59 ppb
2018-06-04	4.96 ppb
2018-06-04	8.95 ppb
2018-06-04	2.93 ppb
2018-06-04	3.21 ppb
2018-06-04	2.27 ppb
2018-06-04	1.53 ppb
2018-06-04	6.36 ppb
2018-07-17	1.14 ppb
2018-07-17	ND
2018-09-05	5.90 ppb
2018-09-05	11.5 ppb
2018-09-05	7.96 ppb
2018-09-05	7.90 ppb
2018-09-05	1.63 ppb
2018-09-05	5.46 ppb
2018-09-05	7.72 ppb
2018-09-06	12.6 ppb
2018-10-02	0.660 ppb
2018-10-09	0.670 ppb
2018-12-07	1.60 ppb
2018-12-07	3.60 ppb
2018-12-07	6.83 ppb
2018-12-07	8.49 ppb
2018-12-07	4.82 ppb
2018-12-07	0.530 ppb
2018-12-07	3.83 ppb
2018-12-07	12.2 ppb
2019-01-08	ND
2019-03-18	0.890 ppb
2019-03-18	1.12 ppb
2019-03-18	6.26 ppb
2019-03-18	5.30 ppb
2019-03-18	4.90 ppb
2019-03-18	ND
2019-03-18	0.770 ppb
2019-03-18	7.01 ppb
2019-05-15	1.23 ppb
2019-05-15	0.730 ppb
2019-06-12	1.59 ppb
2019-06-12	3.82 ppb
2019-06-12	6.80 ppb
2019-06-12	5.61 ppb
2019-06-12	5.46 ppb
2019-06-12	1.13 ppb
2019-06-12	1.98 ppb
2019-06-12	6.87 ppb
2019-07-09	1.23 ppb
2019-07-09	1.83 ppb
2019-09-12	6.92 ppb
2019-09-12	4.05 ppb
2019-09-12	5.59 ppb
2019-09-12	5.45 ppb
2019-09-12	4.59 ppb
2019-09-12	1.08 ppb
2019-09-12	7.00 ppb
2019-09-12	8.05 ppb
2019-10-01	ND
2019-12-09	2.87 ppb
2019-12-09	2.93 ppb
2019-12-09	7.08 ppb
2019-12-09	14.0 ppb
2019-12-09	6.09 ppb
2019-12-09	ND
2019-12-09	0.800 ppb
2019-12-09	11.1 ppb