Know Your Environment. Protect Your Health.

Chloroform

Bear Mountain Water Supply

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.

 

24

Samples

0

Samples exceeding legal limit (MCL)

24

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201842.8 ppb4431.0 ppb - 53.0 ppb
201933.6 ppb5512.0 ppb - 55.0 ppb
202027.7 ppb440.800 ppb - 54.0 ppb
202146.2 ppb4435.2 ppb - 57.0 ppb
202260.6 ppb2255.1 ppb - 66.0 ppb
202349.2 ppb5526.9 ppb - 58.0 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
2018-02-05TTHMS 02061811:342.0 ppb
2018-05-07DBP 05071819-131.0 ppb
2018-07-25TTHM 07251829-145.0 ppb
2018-11-13TTHM 11151803:153.0 ppb
2019-02-05TTHMS 02061903A:112.0 ppb
2019-02-05TTHM 02061903A:112.0 ppb
2019-05-08TTHMS 0508190535.0 ppb
2019-08-07TTHM 0814190754.0 ppb
2019-11-04TTHMS QB19274755.0 ppb
2020-02-05DBP 02062004:116.0 ppb
2020-05-13DBP9 05132006:140.0 ppb
2020-08-13TTHM 0813201354.0 ppb
2020-11-04DBP 11042008-10.800 ppb
2021-02-16TTHM 11042008:135.2 ppb
2021-05-05DBP 05052105:148.6 ppb
2021-08-04TTHMS 08042105C57.0 ppb
2021-11-17TTHMS 11172114-144.0 ppb
2022-05-25TTHMS 0526220366.0 ppb
2022-10-25TTHMS 10262215B:455.1 ppb
2023-01-27TTHMS 01272306-1026.9 ppb
2023-06-15TTHM 06152304:155.1 ppb
2023-10-02TTHM 10042313B:158.0 ppb
2023-10-13TTHMS 12132334:153.0 ppb
2023-12-13TTHM 12132334-153.0 ppb