Know Your Environment. Protect Your Health.

Haloacetic acids (HAA5)

Harris County Municipal Utility District 321

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

0

Samples exceeding legal limit (MCL)

10

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20186.08 ppb441.10 ppb - 11.1 ppb
20198.18 ppb444.20 ppb - 11.6 ppb
20200.275 ppb41ND - 1.10 ppb
20210.450 ppb41ND - 1.80 ppb
2022ND40ND
2023ND40ND

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
2018-01-11AE089114.20 ppb
2018-04-04AE211721.10 ppb
2018-07-12AE330977.90 ppb
2018-10-09AE4292611.1 ppb
2019-01-31AE524137.20 ppb
2019-04-18AE629614.20 ppb
2019-09-25AE8459711.6 ppb
2019-11-07AE888939.70 ppb
2020-02-13AE98421ND
2020-05-28AF130511.10 ppb
2020-09-10AF26996ND
2020-12-15AF37656ND
2021-02-09AF432311.80 ppb
2021-05-18AF54346ND
2021-08-19AF67105ND
2021-11-16AF76782ND
2022-02-10AF84248ND
2022-04-21AF94017ND
2022-09-29AG15424ND
2022-10-25AG18300ND
2023-03-14AG32936ND
2023-05-18AG41055ND
2023-07-20AG49572ND
2023-12-05AG65465ND