Chloroform
Monroe Water System
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.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 25.8 ppb | 64 | 64 | 10.1 ppb - 50.7 ppb |
| 2019 | 33.2 ppb | 66 | 66 | 12.6 ppb - 83.6 ppb |
| 2020 | 26.2 ppb | 32 | 32 | 17.5 ppb - 40.8 ppb |
| 2021 | 22.2 ppb | 32 | 31 | ND - 39.4 ppb |
| 2022 | 25.3 ppb | 32 | 32 | 13.5 ppb - 37.2 ppb |
| 2023 | 24.6 ppb | 32 | 32 | 10.7 ppb - 45.5 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.4 ppb
The EWG Health Guideline of 0.4 ppb for chloroform was based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer and harm to fetal growth and development.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-02-09 | 35374042001 | 22.6 ppb |
| 2018-02-09 | 35374042002 | 22.4 ppb |
| 2018-02-09 | 35374042003 | 11.7 ppb |
| 2018-02-09 | 35374042004 | 23.3 ppb |
| 2018-02-09 | 35374042005 | 23.2 ppb |
| 2018-02-09 | 35374042006 | 23.4 ppb |
| 2018-02-09 | 35374042007 | 10.1 ppb |
| 2018-02-09 | 35374042008 | 22.0 ppb |
| 2018-02-09 | 35374042001 | 22.6 ppb |
| 2018-02-09 | 35374042002 | 22.4 ppb |
| 2018-02-09 | 35374042003 | 11.7 ppb |
| 2018-02-09 | 35374042004 | 23.3 ppb |
| 2018-02-09 | 35374042005 | 23.2 ppb |
| 2018-02-09 | 35374042006 | 23.4 ppb |
| 2018-02-09 | 35374042007 | 10.1 ppb |
| 2018-02-09 | 35374042008 | 22.0 ppb |
| 2018-05-11 | 35391887001 | 16.6 ppb |
| 2018-05-11 | 35391887002 | 16.3 ppb |
| 2018-05-11 | 35391887003 | 15.8 ppb |
| 2018-05-11 | 35391887004 | 27.4 ppb |
| 2018-05-11 | 35391887005 | 16.1 ppb |
| 2018-05-11 | 35391887006 | 12.7 ppb |
| 2018-05-11 | 35391887007 | 18.7 ppb |
| 2018-05-11 | 35391887008 | 23.1 ppb |
| 2018-05-11 | 35391887001 | 16.6 ppb |
| 2018-05-11 | 35391887002 | 16.3 ppb |
| 2018-05-11 | 35391887003 | 15.8 ppb |
| 2018-05-11 | 35391887004 | 27.4 ppb |
| 2018-05-11 | 35391887005 | 16.1 ppb |
| 2018-05-11 | 35391887006 | 12.7 ppb |
| 2018-05-11 | 35391887007 | 18.7 ppb |
| 2018-05-11 | 35391887008 | 23.1 ppb |
| 2018-08-08 | 35410403001 | 49.5 ppb |
| 2018-08-08 | 35410403002 | 43.3 ppb |
| 2018-08-08 | 35410403003 | 47.0 ppb |
| 2018-08-08 | 35410403004 | 48.2 ppb |
| 2018-08-08 | 35410403005 | 50.7 ppb |
| 2018-08-08 | 35410403006 | 40.6 ppb |
| 2018-08-08 | 35410403007 | 44.9 ppb |
| 2018-08-08 | 35410403008 | 48.6 ppb |
| 2018-08-08 | 35410403001 | 49.5 ppb |
| 2018-08-08 | 35410403002 | 43.3 ppb |
| 2018-08-08 | 35410403003 | 47.0 ppb |
| 2018-08-08 | 35410403004 | 48.2 ppb |
| 2018-08-08 | 35410403005 | 50.7 ppb |
| 2018-08-08 | 35410403006 | 40.6 ppb |
| 2018-08-08 | 35410403007 | 44.9 ppb |
| 2018-08-08 | 35410403008 | 48.6 ppb |
| 2018-11-05 | 35429700001 | 17.9 ppb |
| 2018-11-05 | 35429700002 | 18.5 ppb |
| 2018-11-05 | 35429700003 | 18.1 ppb |
| 2018-11-05 | 35429700004 | 18.7 ppb |
| 2018-11-05 | 35429700005 | 18.4 ppb |
| 2018-11-05 | 35429700006 | 18.9 ppb |
| 2018-11-05 | 35429700007 | 19.2 ppb |
| 2018-11-05 | 35429700008 | 18.2 ppb |
| 2018-11-05 | 35429700001 | 17.9 ppb |
| 2018-11-05 | 35429700002 | 18.5 ppb |
| 2018-11-05 | 35429700003 | 18.1 ppb |
| 2018-11-05 | 35429700004 | 18.7 ppb |
| 2018-11-05 | 35429700005 | 18.4 ppb |
| 2018-11-05 | 35429700006 | 18.9 ppb |
| 2018-11-05 | 35429700007 | 19.2 ppb |
| 2018-11-05 | 35429700008 | 18.2 ppb |
| 2019-02-06 | 35446801001 | 30.5 ppb |
| 2019-02-06 | 35446801002 | 30.3 ppb |
| 2019-02-06 | 35446801003 | 30.0 ppb |
| 2019-02-06 | 35446801004 | 30.4 ppb |
| 2019-02-06 | 35446801005 | 30.8 ppb |
| 2019-02-06 | 35446801006 | 31.5 ppb |
| 2019-02-06 | 35446801007 | 83.6 ppb |
| 2019-02-06 | 35446801008 | 30.3 ppb |
| 2019-02-06 | 35446801001 | 30.5 ppb |
| 2019-02-06 | 35446801002 | 30.3 ppb |
| 2019-02-06 | 35446801003 | 30.0 ppb |
| 2019-02-06 | 35446801004 | 30.4 ppb |
| 2019-02-06 | 35446801005 | 30.8 ppb |
| 2019-02-06 | 35446801006 | 31.5 ppb |
| 2019-02-06 | 35446801007 | 83.6 ppb |
| 2019-02-06 | 35446801008 | 30.3 ppb |
| 2019-03-12 | 35454648001 | 23.5 ppb |
| 2019-03-12 | 35454648001 | 23.5 ppb |
| 2019-05-08 | 35467838001 | 45.5 ppb |
| 2019-05-08 | 35467838002 | 44.1 ppb |
| 2019-05-08 | 35467838003 | 44.5 ppb |
| 2019-05-08 | 35467838004 | 44.0 ppb |
| 2019-05-08 | 35467838005 | 42.8 ppb |
| 2019-05-08 | 35467838006 | 36.2 ppb |
| 2019-05-08 | 35467838007 | 45.0 ppb |
| 2019-05-08 | 35467838008 | 47.6 ppb |
| 2019-05-08 | 35467838001 | 45.5 ppb |
| 2019-05-08 | 35467838002 | 44.1 ppb |
| 2019-05-08 | 35467838003 | 44.5 ppb |
| 2019-05-08 | 35467838004 | 44.0 ppb |
| 2019-05-08 | 35467838005 | 42.8 ppb |
| 2019-05-08 | 35467838006 | 36.2 ppb |
| 2019-05-08 | 35467838007 | 45.0 ppb |
| 2019-05-08 | 35467838008 | 47.6 ppb |
| 2019-08-01 | 35487255001 | 43.7 ppb |
| 2019-08-01 | 35487255002 | 37.3 ppb |
| 2019-08-01 | 35487255003 | 37.4 ppb |
| 2019-08-01 | 35487255004 | 37.3 ppb |
| 2019-08-01 | 35487255005 | 36.6 ppb |
| 2019-08-01 | 35487255006 | 37.5 ppb |
| 2019-08-01 | 35487255007 | 38.5 ppb |
| 2019-08-01 | 35487255008 | 36.3 ppb |
| 2019-08-01 | 35487255001 | 43.7 ppb |
| 2019-08-01 | 35487255002 | 37.3 ppb |
| 2019-08-01 | 35487255003 | 37.4 ppb |
| 2019-08-01 | 35487255004 | 37.3 ppb |
| 2019-08-01 | 35487255005 | 36.6 ppb |
| 2019-08-01 | 35487255006 | 37.5 ppb |
| 2019-08-01 | 35487255007 | 38.5 ppb |
| 2019-08-01 | 35487255008 | 36.3 ppb |
| 2019-11-07 | 35510955001 | 20.4 ppb |
| 2019-11-07 | 35510955002 | 14.0 ppb |
| 2019-11-07 | 35510955003 | 14.8 ppb |
| 2019-11-07 | 35510955004 | 13.8 ppb |
| 2019-11-07 | 35510955005 | 14.4 ppb |
| 2019-11-07 | 35510955006 | 14.3 ppb |
| 2019-11-07 | 35510955007 | 15.4 ppb |
| 2019-11-07 | 35510955008 | 12.6 ppb |
| 2019-11-07 | 35510955001 | 20.4 ppb |
| 2019-11-07 | 35510955002 | 14.0 ppb |
| 2019-11-07 | 35510955003 | 14.8 ppb |
| 2019-11-07 | 35510955004 | 13.8 ppb |
| 2019-11-07 | 35510955005 | 14.4 ppb |
| 2019-11-07 | 35510955006 | 14.3 ppb |
| 2019-11-07 | 35510955007 | 15.4 ppb |
| 2019-11-07 | 35510955008 | 12.6 ppb |
| 2020-02-07 | 35529452001 | 17.5 ppb |
| 2020-02-07 | 35529452002 | 17.9 ppb |
| 2020-02-07 | 35529452003 | 17.9 ppb |
| 2020-02-07 | 35529452004 | 18.0 ppb |
| 2020-02-07 | 35529452005 | 17.8 ppb |
| 2020-02-07 | 35529452006 | 18.4 ppb |
| 2020-02-07 | 35529452007 | 21.7 ppb |
| 2020-02-07 | 35529452008 | 17.7 ppb |
| 2020-05-01 | 35547130001 | 24.8 ppb |
| 2020-05-01 | 35547130002 | 25.0 ppb |
| 2020-05-01 | 35547130003 | 26.4 ppb |
| 2020-05-01 | 35547130004 | 25.9 ppb |
| 2020-05-01 | 35547130005 | 25.1 ppb |
| 2020-05-01 | 35547130006 | 24.7 ppb |
| 2020-05-01 | 35547130007 | 27.2 ppb |
| 2020-05-01 | 35547130008 | 25.5 ppb |
| 2020-08-13 | 35570919001 | 40.6 ppb |
| 2020-08-13 | 35570919002 | 39.7 ppb |
| 2020-08-13 | 35570919003 | 40.8 ppb |
| 2020-08-13 | 35570919004 | 39.9 ppb |
| 2020-08-13 | 35570919005 | 39.8 ppb |
| 2020-08-13 | 35570919006 | 38.7 ppb |
| 2020-08-13 | 35570919007 | 40.3 ppb |
| 2020-08-13 | 35570919008 | 40.2 ppb |
| 2020-11-02 | 35589216001 | 20.4 ppb |
| 2020-11-02 | 35589216002 | 21.1 ppb |
| 2020-11-02 | 35589216003 | 20.1 ppb |
| 2020-11-02 | 35589216004 | 21.6 ppb |
| 2020-11-02 | 35589216005 | 20.4 ppb |
| 2020-11-02 | 35589216006 | 19.4 ppb |
| 2020-11-02 | 35589216007 | 21.4 ppb |
| 2020-11-02 | 35589216008 | 23.1 ppb |
| 2021-02-04 | 35609874001 | 14.9 ppb |
| 2021-02-04 | 35609874002 | 15.3 ppb |
| 2021-02-04 | 35609874003 | 15.0 ppb |
| 2021-02-04 | 35609874004 | 14.7 ppb |
| 2021-02-04 | 35609874005 | 14.7 ppb |
| 2021-02-04 | 35609874006 | 14.3 ppb |
| 2021-02-04 | 35609874007 | ND |
| 2021-02-04 | 35609874008 | 14.9 ppb |
| 2021-05-06 | 35631676001 | 27.3 ppb |
| 2021-05-06 | 35631676002 | 26.2 ppb |
| 2021-05-06 | 35631676003 | 32.0 ppb |
| 2021-05-06 | 35631676004 | 31.6 ppb |
| 2021-05-06 | 35631676005 | 29.2 ppb |
| 2021-05-06 | 35631676006 | 24.1 ppb |
| 2021-05-06 | 35631676007 | 22.2 ppb |
| 2021-05-06 | 35631676008 | 23.8 ppb |
| 2021-08-11 | 35655886001 | 34.3 ppb |
| 2021-08-11 | 35655886002 | 35.4 ppb |
| 2021-08-11 | 35655886003 | 35.2 ppb |
| 2021-08-11 | 35655886004 | 36.2 ppb |
| 2021-08-11 | 35655886005 | 35.5 ppb |
| 2021-08-11 | 35655886006 | 34.1 ppb |
| 2021-08-11 | 35655886007 | 36.1 ppb |
| 2021-08-11 | 35655886008 | 39.4 ppb |
| 2021-11-09 | 35676728001 | 14.1 ppb |
| 2021-11-09 | 35676728002 | 13.3 ppb |
| 2021-11-09 | 35676728003 | 11.9 ppb |
| 2021-11-09 | 35676728004 | 12.5 ppb |
| 2021-11-09 | 35676728005 | 12.1 ppb |
| 2021-11-09 | 35676728006 | 14.4 ppb |
| 2021-11-09 | 35676728007 | 12.1 ppb |
| 2021-11-09 | 35676728008 | 14.3 ppb |
| 2022-02-02 | 35695215001 | 14.2 ppb |
| 2022-02-02 | 35695215002 | 14.1 ppb |
| 2022-02-02 | 35695215003 | 14.7 ppb |
| 2022-02-02 | 35695215004 | 13.9 ppb |
| 2022-02-02 | 35695215005 | 13.5 ppb |
| 2022-02-02 | 35695215007 | 14.8 ppb |
| 2022-02-02 | 35695215008 | 13.5 ppb |
| 2022-02-03 | 35695215006 | 13.6 ppb |
| 2022-05-12 | 35718290001 | 25.3 ppb |
| 2022-05-12 | 35718290002 | 24.1 ppb |
| 2022-05-12 | 35718290003 | 25.6 ppb |
| 2022-05-12 | 35718290004 | 25.2 ppb |
| 2022-05-12 | 35718290005 | 24.2 ppb |
| 2022-05-12 | 35718290006 | 27.2 ppb |
| 2022-05-12 | 35718290007 | 24.7 ppb |
| 2022-05-12 | 35718290008 | 27.9 ppb |
| 2022-08-04 | 35737488001 | 35.5 ppb |
| 2022-08-04 | 35737488002 | 36.4 ppb |
| 2022-08-04 | 35737488003 | 35.9 ppb |
| 2022-08-04 | 35737488004 | 35.5 ppb |
| 2022-08-04 | 35737488005 | 36.5 ppb |
| 2022-08-04 | 35737488006 | 34.7 ppb |
| 2022-08-04 | 35737488007 | 36.0 ppb |
| 2022-08-04 | 35737488008 | 37.2 ppb |
| 2022-11-03 | 35758052001 | 23.6 ppb |
| 2022-11-03 | 35758052002 | 30.5 ppb |
| 2022-11-03 | 35758052003 | 28.8 ppb |
| 2022-11-03 | 35758052004 | 24.2 ppb |
| 2022-11-03 | 35758052005 | 25.4 ppb |
| 2022-11-03 | 35758052006 | 21.3 ppb |
| 2022-11-03 | 35758052007 | 24.8 ppb |
| 2022-11-03 | 35758052008 | 27.3 ppb |
| 2023-02-03 | 35776923001 | 15.9 ppb |
| 2023-02-03 | 35776923002 | 15.9 ppb |
| 2023-02-03 | 35776923003 | 15.6 ppb |
| 2023-02-03 | 35776923004 | 16.2 ppb |
| 2023-02-03 | 35776923005 | 16.2 ppb |
| 2023-02-03 | 35776923006 | 15.6 ppb |
| 2023-02-03 | 35776923007 | 16.1 ppb |
| 2023-02-03 | 35776923008 | 21.8 ppb |
| 2023-05-03 | 35797763001 | 25.5 ppb |
| 2023-05-03 | 35797763002 | 23.2 ppb |
| 2023-05-03 | 35797763003 | 24.1 ppb |
| 2023-05-03 | 35797763004 | 25.9 ppb |
| 2023-05-03 | 35797763005 | 24.0 ppb |
| 2023-05-03 | 35797763006 | 24.3 ppb |
| 2023-05-03 | 35797763007 | 23.6 ppb |
| 2023-05-03 | 35797763008 | 23.8 ppb |
| 2023-08-02 | 35818360001 | 44.9 ppb |
| 2023-08-02 | 35818360002 | 41.1 ppb |
| 2023-08-02 | 35818360003 | 43.0 ppb |
| 2023-08-02 | 35818360004 | 45.5 ppb |
| 2023-08-02 | 35818360005 | 43.8 ppb |
| 2023-08-02 | 35818360006 | 42.9 ppb |
| 2023-08-02 | 35818360007 | 43.4 ppb |
| 2023-08-02 | 35818360008 | 43.3 ppb |
| 2023-11-02 | 35839243001 | 10.7 ppb |
| 2023-11-02 | 35839243002 | 19.4 ppb |
| 2023-11-02 | 35839243003 | 14.6 ppb |
| 2023-11-02 | 35839243004 | 13.3 ppb |
| 2023-11-02 | 35839243005 | 12.7 ppb |
| 2023-11-02 | 35839243006 | 11.4 ppb |
| 2023-11-02 | 35839243007 | 14.3 ppb |
| 2023-11-02 | 35839243008 | 16.4 ppb |