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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Dover 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

 

114

Samples

0

Samples exceeding legal limit (MCL)

54

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20140.230 ppb101ND - 2.30 ppb
20150.229 ppb71ND - 1.60 ppb
20160.691 ppb2312ND - 3.20 ppb
20171.34 ppb2614ND - 3.90 ppb
20181.02 ppb2515ND - 4.10 ppb
20190.652 ppb2311ND - 2.40 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
2014-02-18A400694002ND
2014-05-08A402208001ND
2014-07-10A404706001ND
2014-07-14A404793001ND
2014-07-14A404793003ND
2014-07-23A405333001ND
2014-07-23A405333002ND
2014-07-23A4053330042.30 ppb
2014-08-07A406202001ND
2014-11-03A408858001ND
2015-07-21A505471001ND
2015-07-21A505471002ND
2015-07-21A505471003ND
2015-07-21A505471004ND
2015-07-23A505633001ND
2015-07-23A505633002ND
2015-07-23A5056330031.60 ppb
2016-02-10B6006430010.700 ppb
2016-02-10B6006430021.000 ppb
2016-02-10B600643003ND
2016-02-10B6006430041.70 ppb
2016-05-17B602906001ND
2016-05-17B6029060020.500 ppb
2016-05-17B6029060030.600 ppb
2016-05-17B6029060041.10 ppb
2016-07-06B605223001ND
2016-07-06B605223003ND
2016-07-07B605299002ND
2016-07-07B605299003ND
2016-07-07B6052990041.30 ppb
2016-07-13B605689002ND
2016-07-25B606384002ND
2016-08-16B607567001ND
2016-08-16B6075670020.600 ppb
2016-08-16B607567003ND
2016-08-16B6075670040.800 ppb
2016-11-14B6101940013.20 ppb
2016-11-14B6101940022.50 ppb
2016-11-14B610194003ND
2016-11-14B6101940041.90 ppb
2017-02-15B7006920012.30 ppb
2017-02-15B7006920022.30 ppb
2017-02-15B700692003ND
2017-02-15B7006920042.30 ppb
2017-05-12B702494001ND
2017-05-16B7025730013.90 ppb
2017-05-16B7025730023.40 ppb
2017-05-16B702573003ND
2017-05-16B7025730041.60 ppb
2017-06-01B703156002ND
2017-07-19B705657001ND
2017-07-19B705657002ND
2017-07-19B705657004ND
2017-07-20B705749002ND
2017-07-20B7057490043.90 ppb
2017-07-20B705749006ND
2017-08-14B7070450012.90 ppb
2017-08-14B7070450022.50 ppb
2017-08-14B707045003ND
2017-08-14B7070450041.20 ppb
2017-10-10B709124001ND
2017-10-10B709124002ND
2017-11-15B7098940013.30 ppb
2017-11-15B7098940023.10 ppb
2017-11-15B7098940030.900 ppb
2017-11-15B7098940041.20 ppb
2018-01-22B800282001ND
2018-01-22B800282002ND
2018-02-12B8005580012.90 ppb
2018-02-12B8005580022.60 ppb
2018-02-12B800558003ND
2018-02-12B8005580041.40 ppb
2018-03-27B801275001ND
2018-04-19B801796001ND
2018-05-15B802449002ND
2018-05-17B8026010011.000 ppb
2018-05-17B8026010020.500 ppb
2018-05-17B8026010032.40 ppb
2018-05-18B8026430010.600 ppb
2018-07-24B805761001ND
2018-07-24B8057610021.40 ppb
2018-08-15B806964001ND
2018-08-15B8069550010.500 ppb
2018-08-15B8069550020.700 ppb
2018-08-15B8069550030.900 ppb
2018-08-15B8069550044.10 ppb
2018-09-05B807804001ND
2018-11-15B809631001ND
2018-11-15B8096310021.000 ppb
2018-11-15B8096310033.20 ppb
2018-11-15B8096310042.20 ppb
2019-02-11B900756001ND
2019-02-11B9007560020.700 ppb
2019-02-11B9007560032.40 ppb
2019-02-11B9007560041.60 ppb
2019-04-11B901990001ND
2019-05-15B902880001ND
2019-05-15B902880002ND
2019-05-15B9028800030.600 ppb
2019-05-15B9028800041.000 ppb
2019-07-02B904902001ND
2019-07-02B904902002ND
2019-07-10B905242002ND
2019-07-10B905242004ND
2019-07-10B9052420051.80 ppb
2019-08-13B9072490010.500 ppb
2019-08-13B9072490020.500 ppb
2019-08-13B907249003ND
2019-08-13B9072490042.00 ppb
2019-11-14B910098001ND
2019-11-14B910096001ND
2019-11-14B910096002ND
2019-11-14B9100960032.20 ppb
2019-11-14B9100960041.70 ppb