Know Your Environment. Protect Your Health.

Haloacetic acids (HAA5)

Bear Mountain Water Supply

Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of five haloacetic acids regulated by federal standards includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid. Read More.

Haloacetic acids are harmful during pregnancy and may increase the risk of cancer. Haloacetic acids are� genotoxic, which means that they induce mutations and DNA damage. Multiple studies by the National Toxicology Program have demonstrated the cancer-causing properties of individual haloacetic acids in laboratory animals. The Department of Health and Human Services is currently considering listing di- or tri-haloacetic acids for possible inclusion in its comprehensive Report on Carcinogens.

Click here to read more about disinfection byproducts.

 

24

Samples

4

Samples exceeding legal limit (MCL)

24

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201839.7 ppb4416.9 ppb - 65.0 ppb
201927.6 ppb5510.4 ppb - 55.0 ppb
202048.7 ppb4414.6 ppb - 77.0 ppb
202130.6 ppb449.83 ppb - 50.0 ppb
202261.7 ppb2253.4 ppb - 70.0 ppb
202325.8 ppb5514.1 ppb - 48.0 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 the group of five haloacetic acids, or HAA5, was defined in a peer-reviewed scientific study by EWG and represents a one-in-a-million lifetime cancer risk level. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL): 60 ppb

The legal limit for the group of five haloacetic acids (HAA5), established in 1998, was based on the need for residual disinfectant levels in water served to customers and the cost of treatment. This limit does not fully protect against the risk of cancer and harm to the developing fetus due to exposure to haloacetic acids.

ppb = parts per billion

All test results

Date Lab ID Result
2018-02-05THAAS 02061811:416.9 ppb
2018-05-07HAA5 05071819-230.0 ppb
2018-07-25HAA5 08091821-665.0 ppb
2018-11-13HAA5 11151803: 247.0 ppb
2019-02-05HAA5 02061903A:210.4 ppb
2019-02-05HAA5S 02061903A:110.4 ppb
2019-05-07HAA5S 0509190521.0 ppb
2019-08-07HAA5 0814190755.0 ppb
2019-11-04HAA5S QB19274841.0 ppb
2020-02-04DBP 02062004:214.6 ppb
2020-05-13DBP9 05132006:231.0 ppb
2020-08-13HAA5 08132013:272.0 ppb
2020-11-04DBP 11042008-277.0 ppb
2021-02-16HAA5 11042008:29.83 ppb
2021-05-05DBP 05052105:217.5 ppb
2021-08-03HAA5S 08042105C:250.0 ppb
2021-11-17HAA5S 11172114:245.0 ppb
2022-09-14HAA5S 09142230-470.0 ppb
2022-10-25HAA5S 10262215B:553.4 ppb
2023-01-19HAA5S 01192309-120.0 ppb
2023-06-15HAA5 06152304:232.7 ppb
2023-09-26HAA5 10042313B248.0 ppb
2023-10-06HAA5 12132334:214.1 ppb
2023-12-06HAA5 12132334-214.1 ppb