Dibromochloromethane
Bear Mountain Water Supply
Dibromochloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Dibromochloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.
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 | 1.000 ppb | 4 | 4 | 0.500 ppb - 1.40 ppb |
| 2019 | 1.04 ppb | 5 | 5 | 0.700 ppb - 2.20 ppb |
| 2020 | 0.825 ppb | 4 | 3 | ND - 1.80 ppb |
| 2021 | 1.19 ppb | 4 | 4 | 0.860 ppb - 1.70 ppb |
| 2022 | 1.17 ppb | 2 | 2 | 1.10 ppb - 1.23 ppb |
| 2023 | 0.810 ppb | 5 | 4 | ND - 1.10 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.1 ppb
The EWG Health Guideline of 0.1 ppb for dibromochloromethane 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 |
|---|---|---|
| 2018-02-05 | TTHMS 02061811:3 | 1.000 ppb |
| 2018-05-07 | DBP 05071819-1 | 0.500 ppb |
| 2018-07-25 | TTHM 07251829-1 | 1.40 ppb |
| 2018-11-13 | TTHM 11151803:1 | 1.10 ppb |
| 2019-02-05 | TTHMS 02061903A:1 | 0.700 ppb |
| 2019-02-05 | TTHM 02061903A:1 | 0.700 ppb |
| 2019-05-08 | TTHMS 05081905 | 0.800 ppb |
| 2019-08-07 | TTHM 08141907 | 2.20 ppb |
| 2019-11-04 | TTHMS QB192747 | 0.800 ppb |
| 2020-02-05 | DBP 02062004:1 | 0.700 ppb |
| 2020-05-13 | DBP9 05132006:1 | ND |
| 2020-08-13 | TTHM 08132013 | 1.80 ppb |
| 2020-11-04 | DBP 11042008-1 | 0.800 ppb |
| 2021-02-16 | TTHM 11042008:1 | 0.990 ppb |
| 2021-05-05 | DBP 05052105:1 | 0.860 ppb |
| 2021-08-04 | TTHMS 08042105C | 1.70 ppb |
| 2021-11-17 | TTHMS 11172114-1 | 1.20 ppb |
| 2022-05-25 | TTHMS 05262203 | 1.10 ppb |
| 2022-10-25 | TTHMS 10262215B:4 | 1.23 ppb |
| 2023-01-27 | TTHMS 01272306-10 | ND |
| 2023-06-15 | TTHM 06152304:1 | 1.05 ppb |
| 2023-10-02 | TTHM 10042313B:1 | 0.800 ppb |
| 2023-10-13 | TTHMS 12132334:1 | 1.10 ppb |
| 2023-12-13 | TTHM 12132334-1 | 1.10 ppb |