Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

Sunbelt Fresh Water Supply District Oakwilde Subdivision

Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform. Read More.

Studies conducted in the U.S. and Europe have found that drinking tap water that carries disinfection byproducts increases the risk of developing bladder cancer. In animal studies, all trihalomethanes cause liver, kidney and intestinal tumors. Some human epidemiological studies also reported an association between disinfection byproducts and an increased risk of problems during pregnancy, including spontaneous miscarriage, cardiovascular defects, neural tube defects and low birth weight.

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

Click here to read more about disinfection byproducts.

 

48

Samples

0

Samples exceeding legal limit (MCL)

27

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20189.56 ppb86ND - 25.2 ppb
20192.74 ppb84ND - 7.70 ppb
20203.20 ppb84ND - 8.80 ppb
20212.39 ppb84ND - 7.90 ppb
20226.51 ppb85ND - 14.4 ppb
20237.09 ppb84ND - 16.3 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.15 ppb

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

EPA Maximum Contaminant
Level (MCL): 80 ppb

The legal limit for the group of four trihalomethanes, 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 due to exposure to trihalomethanes.

ppb = parts per billion

All test results

Date Lab ID Result
2018-01-29AE11219ND
2018-01-29AE112141.70 ppb
2018-04-10AE2185323.5 ppb
2018-04-10AE2185125.2 ppb
2018-08-28AE3864611.4 ppb
2018-08-28AE386505.70 ppb
2018-10-12AE43396ND
2018-10-12AE433979.00 ppb
2019-01-30AE521593.40 ppb
2019-01-30AE521774.30 ppb
2019-04-15AE622657.70 ppb
2019-04-15AE62266ND
2019-08-05AE77012ND
2019-08-05AE77008ND
2019-12-06AE91631ND
2019-12-18AE926946.50 ppb
2020-02-19AE989583.10 ppb
2020-02-19AE98959ND
2020-05-20AF12083ND
2020-05-20AF121127.00 ppb
2020-08-18AF24029ND
2020-08-18AF240308.80 ppb
2020-10-14AF305616.70 ppb
2020-10-14AF30562ND
2021-02-03AF424225.60 ppb
2021-02-03AF42442ND
2021-04-29AF51874ND
2021-04-29AF518762.80 ppb
2021-08-18AF668397.90 ppb
2021-08-18AF66843ND
2021-10-14AF73535ND
2021-10-14AF735402.80 ppb
2022-01-26AF81863ND
2022-01-26AF818951.000 ppb
2022-05-26AF98649ND
2022-05-26AF9865613.8 ppb
2022-08-22AG1020311.3 ppb
2022-08-22AG1020511.6 ppb
2022-12-15AG21928ND
2022-12-15AG2193214.4 ppb
2023-03-07AG3184913.2 ppb
2023-03-07AG31850ND
2023-05-03AG39101ND
2023-05-03AG3910711.0 ppb
2023-07-19AG49295ND
2023-07-19AG4933216.2 ppb
2023-11-27Q235078000116.3 ppb
2023-11-27Q2350780002ND