Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

City of Chubbuck

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.

 

119

Samples

0

Samples exceeding legal limit (MCL)

63

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.314 ppb122ND - 2.02 ppb
20190.649 ppb152ND - 6.80 ppb
20204.46 ppb2012ND - 12.1 ppb
20214.62 ppb2415ND - 14.3 ppb
20224.78 ppb2416ND - 14.1 ppb
20234.34 ppb2416ND - 11.5 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
2018-02-14VI80208701ND
2018-02-21VI80212801ND
2018-04-24VI80420901ND
2018-04-24VI80420902ND
2018-04-24VI80420903ND
2018-04-24VI80420904ND
2018-07-31VI80740201ND
2018-07-31VI80740202ND
2018-08-01DI808021012.02 ppb
2018-08-01DI808021021.75 ppb
2018-11-07VI81105201ND
2018-11-07VI81105202ND
2019-01-08VI90104601ND
2019-01-16VI90110901ND
2019-03-28VI90320301ND
2019-03-28VI90320401ND
2019-04-10VI90408601ND
2019-05-14VI90512301ND
2019-06-04VI90604901ND
2019-06-11VI90615301ND
2019-07-10VI90712501ND
2019-07-16DI907226012.93 ppb
2019-07-16DI907226026.80 ppb
2019-08-14VI90819101ND
2019-09-04VI90903501ND
2019-10-31VI91031701ND
2019-11-05VI91102401ND
2020-01-21VI00110701ND
2020-02-05VI00202601ND
2020-03-18VI00315701ND
2020-05-04VI00500701ND
2020-05-27DI005229019.68 ppb
2020-05-27DI005229026.89 ppb
2020-05-27DI005229039.51 ppb
2020-05-27DI005229044.37 ppb
2020-06-10VI00617201ND
2020-06-10VI00617202ND
2020-07-28DI007328012.90 ppb
2020-07-28DI007328022.02 ppb
2020-07-28DI007328033.04 ppb
2020-07-28DI007328045.48 ppb
2020-07-29VI00734401ND
2020-10-12VI01013201ND
2020-10-29DI0103200112.0 ppb
2020-10-29DI0103200212.1 ppb
2020-10-29DI0103200312.1 ppb
2020-10-29DI010320049.16 ppb
2021-01-12VI10105901ND
2021-02-10DI102079038.35 ppb
2021-02-10DI102079014.25 ppb
2021-02-10DI102079028.90 ppb
2021-02-10DI102079048.82 ppb
2021-02-23VI10214702ND
2021-02-23VI10214701ND
2021-03-16VI10311101ND
2021-04-20DI10416403ND
2021-04-20DI104164048.46 ppb
2021-04-20DI104164018.36 ppb
2021-04-20VI10416301ND
2021-04-20DI104164028.48 ppb
2021-08-10DI108142033.50 ppb
2021-08-10DI108142042.01 ppb
2021-08-10DI108142022.63 ppb
2021-08-10DI108142011.66 ppb
2021-08-16VI10818202ND
2021-08-16VI10818201ND
2021-11-02DI1110180313.2 ppb
2021-11-02DI1110180213.8 ppb
2021-11-02VI11102001ND
2021-11-02DI111018044.20 ppb
2021-11-02DI1110180114.3 ppb
2022-01-11VI20107401ND
2022-01-11DI201075017.22 ppb
2022-01-11DI201075027.08 ppb
2022-01-11DI2010750312.9 ppb
2022-01-11DI201075047.32 ppb
2022-04-20VI20419001ND
2022-05-10DI205082016.87 ppb
2022-05-10DI2050820211.0 ppb
2022-05-10DI2050820314.1 ppb
2022-05-10DI2050820411.7 ppb
2022-05-16VI20515801ND
2022-07-11VI20710901ND
2022-07-20VI20731701ND
2022-07-27VI20740701ND
2022-08-02DI208028014.09 ppb
2022-08-02DI208028021.08 ppb
2022-08-02DI208028034.88 ppb
2022-08-02DI208028046.76 ppb
2022-08-03VI20805701ND
2022-10-11DI210108014.86 ppb
2022-10-11DI210108025.01 ppb
2022-10-11DI210108034.98 ppb
2022-10-11DI210108044.89 ppb
2022-10-19VI21019301ND
2023-02-15DI3021040110.6 ppb
2023-02-15DI302104026.47 ppb
2023-02-15DI3021040311.5 ppb
2023-02-15DI302104046.13 ppb
2023-02-22VI30216201ND
2023-05-03VI30504501ND
2023-05-09DI305108015.26 ppb
2023-05-09DI3051080210.2 ppb
2023-05-09DI3051080310.8 ppb
2023-05-09DI305108045.12 ppb
2023-06-21VI30635501ND
2023-06-21VI30635502ND
2023-07-18VI30723401ND
2023-07-18DI307260014.31 ppb
2023-07-18DI307260024.59 ppb
2023-07-18DI307260034.48 ppb
2023-07-18DI307260041.73 ppb
2023-08-07VI30809601ND
2023-08-07VI30809602ND
2023-10-02VI31001401ND
2023-10-04DI310045014.87 ppb
2023-10-04DI310045025.98 ppb
2023-10-04DI310045036.33 ppb
2023-10-04DI310045045.87 ppb