Chloroform
Dover City PWS
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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2013 | N/A | 0 | 0 | N/A |
2014 | 0.239 ppb | 30 | 9 | ND - 1.47 ppb |
2015 | 0.0763 ppb | 27 | 2 | ND - 1.34 ppb |
2016 | 0.168 ppb | 28 | 4 | ND - 1.30 ppb |
2017 | 0.1000 ppb | 20 | 2 | ND - 1.20 ppb |
2018 | 0.307 ppb | 15 | 4 | ND - 1.40 ppb |
2019 | 0.365 ppb | 17 | 4 | ND - 2.10 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 |
---|---|---|
2014-02-10 | 14021081 | ND |
2014-02-10 | 14021082 | 0.560 ppb |
2014-02-10 | 14021083 | 0.840 ppb |
2014-02-10 | 14021084 | 0.810 ppb |
2014-02-13 | 14021075 | ND |
2014-02-13 | 14021076 | ND |
2014-02-13 | 14021077 | ND |
2014-02-13 | 14021078 | ND |
2014-05-08 | 14051338 | 0.548 ppb |
2014-05-08 | 14051339 | 0.972 ppb |
2014-05-08 | 14051340 | 0.631 ppb |
2014-05-08 | 14051341 | 1.47 ppb |
2014-05-13 | 14051934 | ND |
2014-05-13 | 14051935 | ND |
2014-05-13 | 14051936 | ND |
2014-05-13 | 14051937 | ND |
2014-05-13 | 14051938 | ND |
2014-08-12 | 14081804 | ND |
2014-08-12 | 14081806 | ND |
2014-08-12 | 14081807 | ND |
2014-08-12 | 14081808 | ND |
2014-08-12 | 14081809 | ND |
2014-08-13 | 14081810 | 0.720 ppb |
2014-08-13 | 14081811 | 0.610 ppb |
2014-11-13 | 14111835 | ND |
2014-11-13 | 14111836 | ND |
2014-11-13 | 14111838 | ND |
2014-11-13 | 14111839 | ND |
2014-11-13 | 14111840 | ND |
2014-11-14 | 14111837 | ND |
2015-02-11 | 15021556 | ND |
2015-02-11 | 15021557 | ND |
2015-02-11 | 15021558 | ND |
2015-02-11 | 15021559 | ND |
2015-02-11 | 15021560 | ND |
2015-02-11 | 15021555 | ND |
2015-05-12 | 15052227 | ND |
2015-05-12 | 15052228 | ND |
2015-05-12 | 15052229 | ND |
2015-05-12 | 15052230 | ND |
2015-05-12 | 15052231 | ND |
2015-05-12 | 15052232 | ND |
2015-08-11 | 15081249 | ND |
2015-08-11 | 15081250 | ND |
2015-08-11 | 15081251 | ND |
2015-08-11 | 15081252 | ND |
2015-08-11 | 15081253 | ND |
2015-08-11 | 15081254 | ND |
2015-08-24 | A150319943 | ND |
2015-09-02 | A150288835 | 0.720 ppb |
2015-09-02 | A150288836 | 1.34 ppb |
2015-11-12 | 15111376 | ND |
2015-11-12 | 15111377 | ND |
2015-11-12 | 15111378 | ND |
2015-11-12 | 15111379 | ND |
2015-11-12 | 15111380 | ND |
2015-11-12 | 15111381 | ND |
2016-02-09 | 16021013 | ND |
2016-02-09 | 16021014 | ND |
2016-02-09 | 16021015 | ND |
2016-02-09 | 16021016 | ND |
2016-02-09 | 16021017 | ND |
2016-02-09 | 16021018 | ND |
2016-05-12 | 16051463 | ND |
2016-05-12 | 16051464 | ND |
2016-05-12 | 16051465 | ND |
2016-05-12 | 16051466 | ND |
2016-05-12 | 16051467 | ND |
2016-05-12 | 16051468 | ND |
2016-06-01 | A160399280 | 1.03 ppb |
2016-06-01 | A160399281 | 1.30 ppb |
2016-08-11 | 16081541 | ND |
2016-08-11 | 16081542 | ND |
2016-08-11 | 16081543 | ND |
2016-08-11 | 16081544 | ND |
2016-08-11 | 16081545 | ND |
2016-08-11 | 16081546 | ND |
2016-09-06 | A160424789 | 1.10 ppb |
2016-09-06 | A160430217 | 1.28 ppb |
2016-11-09 | 16111190 | ND |
2016-11-09 | 16111191 | ND |
2016-11-09 | 16111192 | ND |
2016-11-09 | 16111193 | ND |
2016-11-09 | 16111194 | ND |
2016-11-09 | 16111195 | ND |
2017-02-13 | 17021837 | ND |
2017-02-13 | 17021839 | ND |
2017-02-13 | 17021840 | ND |
2017-02-13 | 17021838 | ND |
2017-02-13 | 17021841 | ND |
2017-02-13 | 17021842 | ND |
2017-05-09 | 17051003 | ND |
2017-05-09 | 17050999 | ND |
2017-05-09 | 17051000 | ND |
2017-05-09 | 17050998 | ND |
2017-05-09 | 17051001 | ND |
2017-05-09 | 17051002 | ND |
2017-08-15 | 17081892 | ND |
2017-08-15 | 17081894 | ND |
2017-08-15 | 17081895 | ND |
2017-08-15 | 17081893 | ND |
2017-08-15 | 17081896 | ND |
2017-08-15 | 17081897 | ND |
2017-09-26 | A170533225 | 0.800 ppb |
2017-09-26 | A170533239 | 1.20 ppb |
2018-02-15 | 18021330 | ND |
2018-02-15 | 18021335 | ND |
2018-02-15 | 18021334 | ND |
2018-02-15 | 18021331 | ND |
2018-02-15 | 18021333 | ND |
2018-02-15 | 18021332 | ND |
2018-08-21 | A180533384 | 1.40 ppb |
2018-08-21 | A180533385 | 1.40 ppb |
2018-08-21 | A180626324 | 0.900 ppb |
2018-08-21 | A180626325 | 0.900 ppb |
2018-11-20 | 18112302 | ND |
2018-11-20 | 18112298 | ND |
2018-11-20 | 18112299 | ND |
2018-11-20 | 18112300 | ND |
2018-11-20 | 18112301 | ND |
2019-02-14 | 19021593 | ND |
2019-02-14 | 19021594 | ND |
2019-02-14 | 18021596 | ND |
2019-02-14 | 19021595 | ND |
2019-02-14 | 19021597 | ND |
2019-02-14 | 19021598 | ND |
2019-05-14 | 19051951 | ND |
2019-05-14 | 19051952 | ND |
2019-05-14 | 19051953 | ND |
2019-05-14 | 19051956 | ND |
2019-05-14 | 19051954 | ND |
2019-05-14 | 19051955 | ND |
2019-08-06 | 9H00922-01 | 1.10 ppb |
2019-08-06 | 9H00922-02 | 1.10 ppb |
2019-08-06 | 9H00922-03 | 1.90 ppb |
2019-08-06 | 9H00922-04 | 2.10 ppb |
2019-08-27 | 19083219 | ND |