Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

New Britain Water Department

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.

 

198

Samples

7

Samples exceeding legal limit (MCL)

198

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201842.3 ppb333319.6 ppb - 76.4 ppb
201939.7 ppb323214.0 ppb - 80.4 ppb
202033.4 ppb353511.0 ppb - 87.1 ppb
202136.5 ppb323213.3 ppb - 70.8 ppb
202241.4 ppb34341.20 ppb - 85.6 ppb
202338.7 ppb323211.3 ppb - 84.5 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
2018-02-22DBP 20048858023.1 ppb
2018-02-22DBP 20048858119.6 ppb
2018-02-22DBP 20048858229.0 ppb
2018-02-22DBP 20048858329.4 ppb
2018-02-22DBP 20048858425.1 ppb
2018-02-22DBP 20048858544.2 ppb
2018-02-22DBP 20048858645.3 ppb
2018-02-22DBP 20048858734.8 ppb
2018-05-16DBP 20049488827.7 ppb
2018-05-16DBP 20049488923.2 ppb
2018-05-16DBP 20049489030.9 ppb
2018-05-16DBP 20049489134.4 ppb
2018-05-16DBP 20049489229.1 ppb
2018-05-16DBP 20049489348.3 ppb
2018-05-16DBP 20049489446.4 ppb
2018-05-16DBP 20049489540.1 ppb
2018-08-14DBP 20050230049.0 ppb
2018-08-14DBP 20050230144.4 ppb
2018-08-14DBP 20050230257.3 ppb
2018-08-14DBP 20050230360.6 ppb
2018-08-14DBP 20050230452.4 ppb
2018-08-14DBP 20050230575.1 ppb
2018-08-14DBP 20050230671.5 ppb
2018-08-14DBP 20050230776.4 ppb
2018-11-14DBP 20051264533.1 ppb
2018-11-14DBP 20051264625.7 ppb
2018-11-14DBP 20051264737.5 ppb
2018-11-14DBP 20051264843.5 ppb
2018-11-14DBP 20051264935.3 ppb
2018-11-14DBP 20051265063.3 ppb
2018-11-14DBP 20051265159.5 ppb
2018-11-14DBP 20051265246.5 ppb
2018-11-14DBP 20051265433.2 ppb
2019-02-20DBP 20052229715.2 ppb
2019-02-20DBP 20052229814.0 ppb
2019-02-20DBP 20052229920.3 ppb
2019-02-20DBP 20052230025.3 ppb
2019-02-20DBP 20052230118.9 ppb
2019-02-20DBP 20052230236.4 ppb
2019-02-20DBP 20052230335.7 ppb
2019-02-20DBP 20052230423.6 ppb
2019-05-16DBP 20053256227.2 ppb
2019-05-16DBP 20053256322.5 ppb
2019-05-16DBP 20053256431.3 ppb
2019-05-16DBP 20053256535.1 ppb
2019-05-16DBP 20053256630.2 ppb
2019-05-16DBP 20053256754.4 ppb
2019-05-16DBP 20053256842.7 ppb
2019-05-16DBP 20053256938.2 ppb
2019-08-20DBP 20054557442.5 ppb
2019-08-20DBP 20054557542.0 ppb
2019-08-20DBP 20054557664.0 ppb
2019-08-20DBP 20054557773.7 ppb
2019-08-20DBP 20054557852.5 ppb
2019-08-20DBP 20054557979.3 ppb
2019-08-20DBP 20054558077.4 ppb
2019-08-20DBP 20054558180.4 ppb
2019-11-21DBP 20055768925.4 ppb
2019-11-21DBP 20055769022.0 ppb
2019-11-21DBP 20055769133.5 ppb
2019-11-21DBP 20055769234.5 ppb
2019-11-21DBP 20055769328.7 ppb
2019-11-21DBP 20055769456.2 ppb
2019-11-21DBP 20055769551.2 ppb
2019-11-21DBP 20055769634.9 ppb
2020-02-20DBP 20056693411.9 ppb
2020-02-20DBP 20056693511.0 ppb
2020-02-20DBP 20056693617.7 ppb
2020-02-20DBP 20056693719.3 ppb
2020-02-20DBP 20056693812.8 ppb
2020-02-20DBP 20056693935.8 ppb
2020-02-20DBP 20056694024.7 ppb
2020-02-20DBP 20056694120.0 ppb
2020-02-20DBP 20056694412.5 ppb
2020-05-13DBP 20057554124.5 ppb
2020-05-13DBP 20057554220.7 ppb
2020-05-13DBP 20057554328.5 ppb
2020-05-13DBP 20057554432.7 ppb
2020-05-13DBP 20057554526.6 ppb
2020-05-13DBP 20057554644.1 ppb
2020-05-13DBP 20057554741.0 ppb
2020-05-13DBP 20057554841.5 ppb
2020-08-11DBP 20058591843.9 ppb
2020-08-11DBP 20058591938.0 ppb
2020-08-11DBP 20058592050.1 ppb
2020-08-11DBP 20058592158.8 ppb
2020-08-11DBP 20058592245.9 ppb
2020-08-11DBP 20058592374.6 ppb
2020-08-11DBP 20058592476.7 ppb
2020-08-11DBP 20058592587.1 ppb
2020-08-11DBP 20058596843.4 ppb
2020-11-18DBP 20059865418.1 ppb
2020-11-18DBP 20059865516.3 ppb
2020-11-18DBP 20059865622.9 ppb
2020-11-18DBP 20059865723.7 ppb
2020-11-18DBP 20059865835.4 ppb
2020-11-18DBP 20059865935.3 ppb
2020-11-18DBP 20059866034.6 ppb
2020-11-18DBP 20059866124.1 ppb
2020-11-18DBP 20059866216.3 ppb
2021-02-17DBP 20060706714.2 ppb
2021-02-17DBP 20060706813.3 ppb
2021-02-17DBP 20060706917.8 ppb
2021-02-17DBP 20060707019.9 ppb
2021-02-17DBP 20060707134.1 ppb
2021-02-17DBP 20060707231.8 ppb
2021-02-17DBP 20060707327.2 ppb
2021-02-17DBP 20060707423.8 ppb
2021-05-20DBP 20061801520.9 ppb
2021-05-20DBP 20061801617.8 ppb
2021-05-20DBP 20061801731.5 ppb
2021-05-20DBP 20061801827.9 ppb
2021-05-20DBP 20061801924.8 ppb
2021-05-20DBP 20061802038.3 ppb
2021-05-20DBP 20061802133.6 ppb
2021-05-20DBP 20061802229.3 ppb
2021-08-11DBP 20062813044.8 ppb
2021-08-11DBP 20062813139.7 ppb
2021-08-11DBP 20062813257.9 ppb
2021-08-11DBP 20062813358.0 ppb
2021-08-11DBP 20062813448.0 ppb
2021-08-11DBP 20062813570.0 ppb
2021-08-11DBP 20062813670.8 ppb
2021-08-11DBP 20062813762.5 ppb
2021-11-17D300103908 30010391028.7 ppb
2021-11-17D300103911 30010391326.9 ppb
2021-11-17D300103914 30010391637.5 ppb
2021-11-17D300103917 30010391940.0 ppb
2021-11-17D300103920 30010392232.4 ppb
2021-11-17D300103923 30010392548.1 ppb
2021-11-17D300103926 30010392853.1 ppb
2021-11-17D300103929 30010393142.5 ppb
2022-02-15D300145868 30014587016.8 ppb
2022-02-15D300145871 30014587314.6 ppb
2022-02-15D300145874 30014587622.8 ppb
2022-02-15D300145877 30014587924.6 ppb
2022-02-15D300145880 30014588217.9 ppb
2022-02-15D300145883 30014588533.9 ppb
2022-02-15D300145886 30014588834.7 ppb
2022-02-15D300145889 30014589125.5 ppb
2022-02-15D300145892 3001458941.20 ppb
2022-05-10D300181521 30018152328.5 ppb
2022-05-10D300181524 30018152627.2 ppb
2022-05-10D300181527 30018152939.3 ppb
2022-05-10D300181530 30018153241.0 ppb
2022-05-10D300181533 30018153531.2 ppb
2022-05-10D300181536 30018153846.8 ppb
2022-05-10D300181539 30018154152.6 ppb
2022-05-10D300181542 30018154442.4 ppb
2022-05-10D300181545 30018154729.1 ppb
2022-08-09D300227257 30022725953.2 ppb
2022-08-09D300227260 30022726246.2 ppb
2022-08-09D300227263 30022726571.5 ppb
2022-08-09D300227266 30022726875.2 ppb
2022-08-09D300227269 30022727161.7 ppb
2022-08-09D300227272 30022727485.6 ppb
2022-08-09D300227275 30022727779.7 ppb
2022-08-09D300227278 30022728080.7 ppb
2022-11-15D300273443 30027344629.4 ppb
2022-11-15D300273450 30027345427.3 ppb
2022-11-15D300273456 30027346137.3 ppb
2022-11-15D300273462 30027346440.0 ppb
2022-11-15D300273465 30027346732.6 ppb
2022-11-15D300273468 30027347055.7 ppb
2022-11-15D300273471 30027347356.1 ppb
2022-11-15D300273474 30027347646.2 ppb
2023-02-09D300307705 30030770712.3 ppb
2023-02-09D300307708 30030771011.3 ppb
2023-02-09D300307711 30030771321.0 ppb
2023-02-09D300307714 30030771618.8 ppb
2023-02-09D300307717 30030771933.5 ppb
2023-02-09D300307720 30030772225.3 ppb
2023-02-09D300307723 30030772514.2 ppb
2023-02-09D300307726 30030772825.2 ppb
2023-05-11D300349330 30034933225.3 ppb
2023-05-11D300349333 30034933522.5 ppb
2023-05-11D300349336 30034933850.8 ppb
2023-05-11D300349339 30034934134.6 ppb
2023-05-11D300349342 30034934428.6 ppb
2023-05-11D300349345 30034934741.0 ppb
2023-05-11D300349348 30034935046.2 ppb
2023-05-11D300349351 30034935336.2 ppb
2023-08-16D300399298 30039930057.4 ppb
2023-08-16D300399301 30039930351.7 ppb
2023-08-16D300399304 30039930680.8 ppb
2023-08-16D300399307 30039930969.9 ppb
2023-08-16D300399310 30039931259.0 ppb
2023-08-16D300399313 30039931584.5 ppb
2023-08-16D300399316 30039931880.1 ppb
2023-08-16D300399319 30039932176.7 ppb
2023-11-16D300447192 30044719421.2 ppb
2023-11-16D300447195 30044719719.3 ppb
2023-11-16D300447198 30044720027.9 ppb
2023-11-16D300447201 30044720328.8 ppb
2023-11-16D300447204 30044720623.7 ppb
2023-11-16D300447207 30044720938.5 ppb
2023-11-16D300447210 30044721239.3 ppb
2023-11-16D300447213 30044721531.7 ppb