Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

Hoosick Falls

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.

 

73

Samples

0

Samples exceeding legal limit (MCL)

39

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.714 ppb143ND - 5.70 ppb
20190.692 ppb134ND - 3.30 ppb
20202.26 ppb129ND - 8.56 ppb
20212.37 ppb1410ND - 10.7 ppb
20221.03 ppb43ND - 2.46 ppb
20231.61 ppb1610ND - 5.83 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
2018-02-20JH1801169ND
2018-02-20JH1801165ND
2018-02-20JH1801171-72ND
2018-02-20JH1801171ND
2018-02-20JH1801167ND
2018-06-18JH1804227ND
2018-06-18JH18042315.70 ppb
2018-06-18JH1804228ND
2018-06-18JH1804229ND
2018-06-18JH18042333.20 ppb
2018-12-11JH1809748ND
2018-12-11JH18097501.10 ppb
2018-12-11JH809749ND
2018-12-11JH1809751ND
2019-03-11JH1901458ND
2019-03-11JH1901454ND
2019-03-11JH1901456ND
2019-03-11JH1901460ND
2019-06-12JH1903673-THM1.10 ppb
2019-06-12JH1903674-THM1.30 ppb
2019-06-12JH1903676-DBP3.30 ppb
2019-06-12JH1903675-THMND
2019-06-12JH19036763.30 ppb
2019-12-09JH1908729ND
2019-12-09JH1908731ND
2019-12-09JH1908730ND
2019-12-09JH1908728ND
2020-06-08JH2003806-THM2.60 ppb
2020-06-08JH2003807-THM3.60 ppb
2020-06-08JH2003808-THM1.40 ppb
2020-06-08JH2003809-THMND
2020-09-14JH20069730.610 ppb
2020-09-14JH20069758.56 ppb
2020-09-14JH20069692.17 ppb
2020-09-14JH20069714.08 ppb
2020-12-14JH2009687ND
2020-12-14JH2009693ND
2020-12-14JH20096910.760 ppb
2020-12-14JH20096893.36 ppb
2021-03-16JH21019961.31 ppb
2021-03-16JH21019941.96 ppb
2021-06-14JH21045441.80 ppb
2021-06-14JH21045466.70 ppb
2021-06-14JH2104542ND
2021-06-14JH21045403.70 ppb
2021-09-20JH210857010.7 ppb
2021-09-20JH21085693.30 ppb
2021-09-20JH21085660.690 ppb
2021-09-20JH21085642.43 ppb
2021-12-06JH2110940ND
2021-12-06JH21109380.520 ppb
2021-12-06JH2110942ND
2021-12-06JH2110944THMND
2022-12-13JH22106330.920 ppb
2022-12-13JH2210635ND
2022-12-13JH22106370.720 ppb
2022-12-13JH22106392.46 ppb
2023-03-21JH2302114ND
2023-03-21JH2302116ND
2023-03-21JH23021181.61 ppb
2023-03-21JH2302112ND
2023-06-06JH23041881.77 ppb
2023-06-06JH23041940.940 ppb
2023-06-06JH23041920.520 ppb
2023-06-06JH23041904.76 ppb
2023-09-12JH23078215.80 ppb
2023-09-12JH23077823ND
2023-09-12JH23078175.83 ppb
2023-09-12JH23078190.830 ppb
2023-12-12JH2310828ND
2023-12-12JH23108260.580 ppb
2023-12-12JH23108243.08 ppb
2023-12-12JH2310822ND