Chloroform

Kent 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

235

Samples

Samples exceeding legal limit (MCL)

195

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	41.2 ppb	47	40	ND - 78.6 ppb
2015	31.5 ppb	37	25	ND - 73.0 ppb
2016	28.8 ppb	36	24	ND - 68.8 ppb
2017	49.5 ppb	43	38	ND - 79.0 ppb
2018	46.3 ppb	36	34	ND - 76.4 ppb
2019	41.6 ppb	36	34	ND - 78.1 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
2014-02-19	1401517-01_TO02	75.3 ppb
2014-02-19	1401517-02_TO02	59.6 ppb
2014-02-19	1401517-03_TO02	69.3 ppb
2014-02-19	1401517-04_TO02	78.2 ppb
2014-02-19	1401517-05_TO02	70.0 ppb
2014-02-19	1401517-06_TO02	62.4 ppb
2014-02-19	1401517-07_TO02	78.1 ppb
2014-02-19	1401517-08_TO02	50.1 ppb
2014-03-17	1401808-05_TO12	ND
2014-03-17	1401808-02_TO12	ND
2014-03-17	1401808-03_TO12	ND
2014-03-17	1401808-04_TO12	0.530 ppb
2014-04-14	1402258-01_TO02	18.8 ppb
2014-04-15	1402286-01_TO02	21.7 ppb
2014-04-15	1402286-02_TO02	37.8 ppb
2014-04-16	1402316-01_TO02	19.2 ppb
2014-04-17	1402339-01_TO02	16.4 ppb
2014-04-17	1402339-02_TO02	47.9 ppb
2014-04-18	1402359-01_TO02	19.8 ppb
2014-04-21	1402378-04_TO12	ND
2014-04-21	1402378-03_TO12	ND
2014-04-21	1402378-02_TO12	ND
2014-05-14	1402678-01_TO02	78.6 ppb
2014-05-14	1402678-02_TO02	53.0 ppb
2014-05-14	1402678-04_TO02	61.2 ppb
2014-05-14	1402678-03_TO02	56.7 ppb
2014-05-15	1402693-01_TO02	41.0 ppb
2014-05-15	1402693-02_TO02	41.7 ppb
2014-05-15	1402693-03_TO02	47.6 ppb
2014-05-15	1402693-04_TO02	41.4 ppb
2014-08-13	1404415-04_TO12	ND
2014-08-14	1408-18110-001	41.0 ppb
2014-08-14	1408-18110-002	54.0 ppb
2014-08-14	1408-18110-003	44.0 ppb
2014-08-14	1408-18110-004	52.0 ppb
2014-08-14	1408-18110-005	54.0 ppb
2014-08-14	1408-18110-006	49.0 ppb
2014-08-14	1408-18110-007	45.0 ppb
2014-08-14	1408-18110-008	41.0 ppb
2014-11-18	1411-25894-001	57.0 ppb
2014-11-18	1411-25894-002	49.0 ppb
2014-11-18	1411-25894-003	64.0 ppb
2014-11-18	1411-25894-004	51.0 ppb
2014-11-18	1411-25894-005	54.0 ppb
2014-11-18	1411-25894-006	47.0 ppb
2014-11-18	1411-25894-007	47.0 ppb
2014-11-18	1411-25894-008	40.0 ppb
2015-02-18	1502-03356-001T	38.0 ppb
2015-02-18	1502-03356-002T	32.0 ppb
2015-02-18	1502-03356-003T	29.0 ppb
2015-02-18	1502-03356-004T	32.0 ppb
2015-02-18	1502-03356-005T	33.0 ppb
2015-02-18	1502-03356-006T	30.0 ppb
2015-02-18	1502-03356-007T	42.0 ppb
2015-02-18	1502-03356-008T	22.0 ppb
2015-03-10	1501510-01_TO12	ND
2015-03-10	1501510-02_TO12	0.550 ppb
2015-04-29	1502029-02_TO12	ND
2015-04-29	1502029-03_TO12	ND
2015-05-13	1505-08683-004	62.0 ppb
2015-05-13	1505-09683-001	64.0 ppb
2015-05-13	1505-09683-002	66.0 ppb
2015-05-13	1505-09683-003	64.0 ppb
2015-05-13	1505-09683-005	63.0 ppb
2015-05-13	1505-09683-006	48.0 ppb
2015-05-13	1505-09683-007	37.0 ppb
2015-05-13	1505-09683-008	44.0 ppb
2015-08-19	1508-17646-001	ND
2015-08-19	1508-17646-002	ND
2015-08-19	1508-17646-003	ND
2015-08-19	1508-17646-004	ND
2015-08-19	1508-17646-005	ND
2015-08-19	1508-17646-006	ND
2015-08-19	1508-17646-007	ND
2015-08-19	1508-17646-008	ND
2015-09-14	1504119-04_TO12	ND
2015-11-17	1511-24948-001	73.0 ppb
2015-11-17	1511-24948-002	53.0 ppb
2015-11-17	1511-24948-003	58.0 ppb
2015-11-17	1511-24948-004	65.0 ppb
2015-11-17	1511-24948-005	61.0 ppb
2015-11-17	1511-24948-006	50.0 ppb
2015-11-17	1511-24948-007	52.0 ppb
2015-11-17	1511-24948-008	47.0 ppb
2016-02-17	1602-03675-001	44.0 ppb
2016-02-17	1602-03675-002	34.0 ppb
2016-02-17	1602-03675-003	18.0 ppb
2016-02-17	1602-03675-004	31.0 ppb
2016-02-17	1602-03675-005	31.0 ppb
2016-02-17	1602-03675-006	39.0 ppb
2016-02-17	1602-03675-007	28.0 ppb
2016-02-17	1602-03675-008	31.0 ppb
2016-03-23	1601576-01_TO12	ND
2016-04-19	1601908-01_TO12	ND
2016-04-19	1601908-03_TO12	ND
2016-05-18	1605-11327-001	ND
2016-05-18	1605-11327-002	ND
2016-05-18	1605-11327-003	ND
2016-05-18	1605-11327-004	ND
2016-05-18	1605-11327-005	ND
2016-05-18	1605-11327-006	ND
2016-05-18	1605-11327-007	ND
2016-05-18	1605-11327-008	ND
2016-07-12	1603230-02_TO12	ND
2016-08-17	1608-19347-001	55.0 ppb
2016-08-17	1608-19347-002	45.0 ppb
2016-08-17	1608-19347-003	56.0 ppb
2016-08-17	1608-19347-004	25.0 ppb
2016-08-17	1608-19347-005	41.0 ppb
2016-08-17	1608-19347-006	50.0 ppb
2016-08-17	1609-19347-007	21.0 ppb
2016-08-17	1609-19347-008	41.0 ppb
2016-11-16	1611480-01	63.1 ppb
2016-11-16	1611480-02	48.5 ppb
2016-11-16	1611480-03	62.1 ppb
2016-11-16	1611480-04	54.2 ppb
2016-11-16	1611480-05	56.6 ppb
2016-11-16	1611480-06	68.8 ppb
2016-11-16	1611480-07	53.0 ppb
2016-11-16	1611480-08	40.2 ppb
2017-02-15	1702292-01	62.1 ppb
2017-02-15	1702292-02	34.9 ppb
2017-02-15	1702292-03	58.0 ppb
2017-02-15	1702292-04	33.3 ppb
2017-02-15	1702292-05	43.6 ppb
2017-02-15	1702292-06	33.9 ppb
2017-02-15	1702292-07	48.5 ppb
2017-02-15	1702292-08	29.2 ppb
2017-03-20	1701538-01_TO12	ND
2017-04-25	1701960-04_TO12	ND
2017-04-25	1701960-01_TO12	ND
2017-05-16	1705442-01	71.6 ppb
2017-05-16	1705442-02	55.2 ppb
2017-05-16	1705442-03	79.0 ppb
2017-05-16	1705442-04	54.7 ppb
2017-05-16	1705442-05	63.9 ppb
2017-05-16	1705442-06	61.9 ppb
2017-05-16	1705442-07	66.0 ppb
2017-05-16	1705442-08	46.5 ppb
2017-08-16	1708376-01	66.8 ppb
2017-08-16	1708376-02	54.8 ppb
2017-08-16	1708376-03	53.3 ppb
2017-08-16	1708376-04	48.8 ppb
2017-08-16	1708376-05	62.8 ppb
2017-08-16	1708376-06	69.6 ppb
2017-08-16	1708376-07	55.6 ppb
2017-08-16	1708376-08	62.3 ppb
2017-08-28	1708-18567-001_T	71.0 ppb
2017-08-28	1708-18567-003_T	71.0 ppb
2017-08-28	1708-18573-001_T	ND
2017-08-28	1708-18567-002_T	72.0 ppb
2017-08-29	1708-18660-001_T	71.0 ppb
2017-08-29	1708-18660-003_T	71.0 ppb
2017-08-29	1708-18660-002_T	71.0 ppb
2017-09-05	1704240-04_TO12	ND
2017-11-21	1711626-01A	64.0 ppb
2017-11-21	1711626-02A	52.2 ppb
2017-11-21	1711626-03A	37.0 ppb
2017-11-21	1711626-04A	62.4 ppb
2017-11-21	1711626-05A	54.7 ppb
2017-11-21	1711626-06A	25.0 ppb
2017-11-21	1711626-07A	55.1 ppb
2017-11-21	1711626-08A	36.3 ppb
2018-02-20	1802387-01	64.1 ppb
2018-02-20	1802387-02	39.3 ppb
2018-02-20	1802387-03	35.7 ppb
2018-02-20	1802387-04	36.7 ppb
2018-02-20	1802387-05	53.9 ppb
2018-02-20	1802387-06	51.5 ppb
2018-02-20	1802387-07	45.7 ppb
2018-02-20	1802387-08	32.7 ppb
2018-03-23	1801470-01_TO12	0.810 ppb
2018-03-23	1801470-02_TO12	0.560 ppb
2018-04-19	1801795-01_TO12	ND
2018-05-16	1805426-01	66.3 ppb
2018-05-16	1805426-02	67.0 ppb
2018-05-16	1805426-03	70.9 ppb
2018-05-16	1805426-04	64.1 ppb
2018-05-16	1805426-05	76.4 ppb
2018-05-16	1805426-06	63.0 ppb
2018-05-16	1805426-07	64.8 ppb
2018-05-16	1805426-08	50.0 ppb
2018-08-15	1808405-01	57.3 ppb
2018-08-15	1808405-02	55.3 ppb
2018-08-15	1808405-03	36.6 ppb
2018-08-15	1808405-04	32.8 ppb
2018-08-15	1808405-05	59.2 ppb
2018-08-15	1808405-06	51.2 ppb
2018-08-15	1808405-07	30.9 ppb
2018-08-15	1808405-08	42.5 ppb
2018-08-30	1803927-02_TO12	ND
2018-11-20	1811551-01	66.4 ppb
2018-11-20	1811551-02	46.5 ppb
2018-11-20	1811551-03	52.0 ppb
2018-11-20	1811551-04	63.6 ppb
2018-11-20	1811551-05	30.5 ppb
2018-11-20	1811551-06	72.7 ppb
2018-11-20	1811551-07	52.2 ppb
2018-11-20	1811551-08	32.7 ppb
2019-02-21	1902421-01	78.1 ppb
2019-02-21	1902421-02	44.3 ppb
2019-02-21	1902421-03	36.1 ppb
2019-02-21	1902421-04	73.7 ppb
2019-02-21	1902421-05	58.1 ppb
2019-02-21	1902421-06	40.3 ppb
2019-02-21	1902421-07	61.9 ppb
2019-02-21	1902421-08	30.6 ppb
2019-03-28	1901506-01_TO12	0.890 ppb
2019-03-28	1901506-02_TO12	0.620 ppb
2019-04-24	1901794-03_TO12	ND
2019-05-15	1905513-01	70.0 ppb
2019-05-15	1905513-02	50.4 ppb
2019-05-15	1905513-03	29.1 ppb
2019-05-15	1905513-04	33.5 ppb
2019-05-15	1905513-05	60.3 ppb
2019-05-15	1905513-06	57.0 ppb
2019-05-15	1905513-07	56.9 ppb
2019-05-15	1905513-08	41.6 ppb
2019-08-21	19H0686-01	56.7 ppb
2019-08-21	19H0686-02	49.2 ppb
2019-08-21	19H0686-03	19.4 ppb
2019-08-21	19H0686-04	47.0 ppb
2019-08-21	19H0686-05	61.2 ppb
2019-08-21	19H0686-06	48.1 ppb
2019-08-21	19H0686-07	48.1 ppb
2019-08-21	19H0686-08	47.8 ppb
2019-09-10	1904181-01_TO12	ND
2019-11-20	19K0605-01	15.2 ppb
2019-11-20	19K0605-02	43.2 ppb
2019-11-20	19K0605-03	13.6 ppb
2019-11-20	19K0605-04	43.7 ppb
2019-11-20	19K0605-05	37.7 ppb
2019-11-20	19K0605-06	39.4 ppb
2019-11-20	19K0605-07	72.7 ppb
2019-11-20	19K0605-08	32.0 ppb