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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Dover Water Commission

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

 

144

Samples

0

Samples exceeding legal limit (MCL)

31

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.233 ppb247ND - 1.09 ppb
20150.182 ppb245ND - 1.60 ppb
20160.175 ppb245ND - 1.23 ppb
20170.230 ppb246ND - 1.08 ppb
20180.210 ppb247ND - 1.06 ppb
20190.0213 ppb241ND - 0.510 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
2014-01-1525051-4ND
2014-01-1525051-3ND
2014-01-1525051-2ND
2014-01-1525051-1ND
2014-03-0525734-2AND
2014-03-0525734-1AND
2014-04-1626316-40.580 ppb
2014-04-1626316-31.000 ppb
2014-04-1626316-2ND
2014-04-1626316-10.710 ppb
2014-06-1827310-2ND
2014-06-1827310-1ND
2014-07-1627840-40.820 ppb
2014-07-1627840-30.740 ppb
2014-07-1627840-2ND
2014-07-1627840-11.09 ppb
2014-09-2629140-2BND
2014-09-2629140-1BND
2014-10-1629456-4ND
2014-10-1629456-30.650 ppb
2014-10-1629456-2ND
2014-10-1629456-1ND
2014-12-1030311-17ND
2014-12-1030311-16ND
2015-01-1530804-4ND
2015-01-1530804-30.600 ppb
2015-01-1530804-2ND
2015-01-1530804-1ND
2015-01-2930990-2ND
2015-01-2930990-1ND
2015-04-16DWS242-4ND
2015-04-16DWS242-3ND
2015-04-16DWS242-2ND
2015-04-16DWS242-1ND
2015-04-16DWS243-2ND
2015-04-16DWS243-1ND
2015-07-14DWS1151-40.600 ppb
2015-07-14DWS1151-30.840 ppb
2015-07-14DWS1151-2ND
2015-07-14DWS1151-11.60 ppb
2015-09-10DWS1518-2AND
2015-09-10DWS1518-1AND
2015-10-15DWS1754-3ND
2015-10-15DWS1754-20.730 ppb
2015-10-15DWS1754-1ND
2015-10-21DWS1794-1ND
2015-11-18DWS1964-2ND
2015-11-18DWS1964-1ND
2016-01-20DWS2269-2ND
2016-01-20DWS2269-1ND
2016-01-22DWS2284-4ND
2016-01-22DWS2284-3ND
2016-01-22DWS2284-2ND
2016-01-22DWS2284-1ND
2016-04-15DWS2805-4ND
2016-04-15DWS2805-3ND
2016-04-15DWS2805-2ND
2016-04-15DWS2805-1ND
2016-04-20DWS2860-2AND
2016-04-20DWS2860-1AND
2016-07-11DWS3345-2ND
2016-07-11DWS3345-1ND
2016-07-20DWS3396-4ND
2016-07-20DWS3396-3ND
2016-07-20DWS3396-2ND
2016-07-20DWS3396-11.23 ppb
2016-10-12DWS3996-40.700 ppb
2016-10-12DWS3996-30.750 ppb
2016-10-12DWS3996-20.710 ppb
2016-10-12DWS3996-10.800 ppb
2016-12-09DWS4357-2AND
2016-12-09DWS4357-1AND
2017-01-20DWS4623-4ND
2017-01-20DWS4623-3ND
2017-01-20DWS4623-2ND
2017-01-20DWS4623-1ND
2017-03-02DWS4896-2AND
2017-03-02DWS4896-1AND
2017-04-28DWS5304-40.970 ppb
2017-04-28DWS5304-30.870 ppb
2017-04-28DWS5304-21.08 ppb
2017-04-28DWS5304-10.890 ppb
2017-05-02DWS5334-2ND
2017-05-02DWS5334-1ND
2017-07-17DWS5949-4ND
2017-07-17DWS5949-30.730 ppb
2017-07-17DWS5949-2ND
2017-07-17DWS5949-10.990 ppb
2017-07-31DWS6081-2ND
2017-07-31DWS6081-1ND
2017-10-06DWS6722-2ND
2017-10-06DWS6722-1ND
2017-10-16DWS6821-4ND
2017-10-16DWS6821-3ND
2017-10-16DWS6821-2ND
2017-10-16DWS6821-1ND
2018-01-16DWS7566-4ND
2018-01-16DWS7566-3ND
2018-01-16DWS7566-2ND
2018-01-16DWS7566-1ND
2018-02-02DWS7708-2AND
2018-02-02DWS7708-1AND
2018-04-16DWS8383-40.710 ppb
2018-04-16DWS8383-3ND
2018-04-16DWS8383-2ND
2018-04-16DWS8383-11.06 ppb
2018-04-26DWS8495-1ND
2018-04-26DWS8494-1ND
2018-07-0618070509-02ND
2018-07-0618070509-01ND
2018-07-1618071320-04ND
2018-07-1618071320-03ND
2018-07-1618071320-020.500 ppb
2018-07-1618071320-010.600 ppb
2018-10-1618101510-04ND
2018-10-1618101510-030.630 ppb
2018-10-1618101510-020.590 ppb
2018-10-1618101510-010.950 ppb
2018-11-0218110119-02ND
2018-11-0218110119-01ND
2019-01-0919010837-02ND
2019-01-0919010837-01ND
2019-01-1519011412-04ND
2019-01-1519011412-03ND
2019-01-1519011412-020.510 ppb
2019-01-1519011412-01ND
2019-04-1719041618-04ND
2019-04-1719041618-03ND
2019-04-1719041618-02ND
2019-04-1719041618-01ND
2019-04-1719041620-02ND
2019-04-1719041620-01ND
2019-07-0519070333-002ND
2019-07-0519070333-001ND
2019-07-1519071230-004ND
2019-07-1519071230-003ND
2019-07-1519071230-002ND
2019-07-1519071230-001ND
2019-10-1719101609-004ND
2019-10-1719101609-003ND
2019-10-1719101609-002ND
2019-10-1719101609-001ND
2019-11-0119103136-002ND
2019-11-0119103136-001ND