Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

City of Bruceville Eddy

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

2

Samples exceeding legal limit (MCL)

14

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201837.6 ppb82ND - 161.0 ppb
20191.01 ppb82ND - 5.90 ppb
20200.463 ppb81ND - 3.70 ppb
20211.75 ppb81ND - 14.0 ppb
20223.16 ppb84ND - 15.2 ppb
20235.89 ppb84ND - 22.0 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
2018-01-22AE09511ND
2018-01-22AE09505ND
2018-04-03AE20994161.0 ppb
2018-04-03AE20992140.0 ppb
2018-08-20AE37573ND
2018-08-20AE37574ND
2018-10-11AE43222ND
2018-10-11AE43224ND
2019-02-25AE55602ND
2019-02-25AE55604ND
2019-05-21AE673275.90 ppb
2019-05-21AE673292.20 ppb
2019-08-08AE77726ND
2019-08-08AE77692ND
2019-10-02AE85494ND
2019-10-02AE85497ND
2020-03-02AF00603ND
2020-03-02AF00611ND
2020-05-13AF10799ND
2020-05-13AF10801ND
2020-08-25AF25008ND
2020-08-25AF25010ND
2020-11-04AF33131ND
2020-11-04AF331333.70 ppb
2021-01-19AF39711ND
2021-01-19AF39713ND
2021-05-25AF55304ND
2021-05-25AF55305ND
2021-07-21AF62930ND
2021-07-21AF62932ND
2021-10-14AF7352114.0 ppb
2021-10-14AF73524ND
2022-01-26AF819122.20 ppb
2022-01-26AF81913ND
2022-05-16AF96937ND
2022-05-16AF9693815.2 ppb
2022-07-06AG033226.90 ppb
2022-07-06AG03324ND
2022-10-03AG15666ND
2022-10-03AG156731.000 ppb
2023-02-13AG2847913.9 ppb
2023-02-14AG28776ND
2023-06-09AG43847ND
2023-06-09AG438496.80 ppb
2023-08-14AG52309ND
2023-08-14AG5231022.0 ppb
2023-10-10AG59074ND
2023-10-10AG590754.40 ppb