Know Your Environment. Protect Your Health.

Chloroform

Mountain Regional Water Special Service District

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.

 

66

Samples

0

Samples exceeding legal limit (MCL)

21

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20184.36 ppb117ND - 21.8 ppb
20190.307 ppb153ND - 2.10 ppb
20200.117 ppb61ND - 0.700 ppb
20213.00 ppb95ND - 14.2 ppb
20220.385 ppb152ND - 4.00 ppb
20230.826 ppb103ND - 6.40 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 Result
2018-03-202.50 ppb
2018-03-20ND
2018-03-2012.5 ppb
2018-06-06ND
2018-06-206.20 ppb
2018-06-2021.8 ppb
2018-06-20ND
2018-08-23ND
2018-09-050.700 ppb
2018-09-131.40 ppb
2018-09-132.90 ppb
2019-01-03ND
2019-01-03ND
2019-01-03ND
2019-01-032.10 ppb
2019-01-24ND
2019-01-24ND
2019-01-24ND
2019-02-25ND
2019-02-25ND
2019-02-25ND
2019-03-20ND
2019-04-18ND
2019-08-281.70 ppb
2019-08-280.800 ppb
2019-11-14ND
2020-03-02ND
2020-07-14ND
2020-07-14ND
2020-09-210.700 ppb
2020-12-04ND
2020-12-30ND
2021-02-022.90 ppb
2021-02-024.00 ppb
2021-03-16ND
2021-06-03ND
2021-06-08ND
2021-08-04ND
2021-08-044.30 ppb
2021-08-0414.2 ppb
2021-12-081.60 ppb
2022-02-171.77 ppb
2022-02-17ND
2022-02-17ND
2022-02-17ND
2022-05-04ND
2022-05-05ND
2022-05-05ND
2022-05-05ND
2022-08-044.00 ppb
2022-08-04ND
2022-08-04ND
2022-09-07ND
2022-12-06ND
2022-12-06ND
2022-12-07ND
2023-03-16ND
2023-06-21ND
2023-09-216.40 ppb
2023-09-21ND
2023-09-211.10 ppb
2023-11-06ND
2023-11-06ND
2023-11-06ND
2023-12-11ND
2023-12-110.760 ppb