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.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 24.6 ppb | 32 | 32 | 11.1 ppb - 42.8 ppb |
| 2015 | 30.8 ppb | 32 | 32 | 14.7 ppb - 57.0 ppb |
| 2016 | 33.0 ppb | 32 | 32 | 15.0 ppb - 66.8 ppb |
| 2017 | 37.1 ppb | 33 | 33 | 11.7 ppb - 66.0 ppb |
| 2018 | 42.3 ppb | 33 | 33 | 19.6 ppb - 76.4 ppb |
| 2019 | 39.7 ppb | 32 | 32 | 14.0 ppb - 80.4 ppb |
ppb = parts per billion
State and national drinking water standards and health guidelines
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 |
|---|---|---|
| 2014-02-18 | 2038-02816CH | 11.6 ppb |
| 2014-02-18 | 2039-02817CH | 17.0 ppb |
| 2014-02-18 | 2040-02818CH | 27.9 ppb |
| 2014-02-18 | 2041-02819CH | 15.2 ppb |
| 2014-02-18 | 2043-02820CH | 11.1 ppb |
| 2014-02-18 | 2044-02821CH | 12.7 ppb |
| 2014-02-18 | 2045-02822CH | 27.8 ppb |
| 2014-02-18 | 2046-02823CH | 29.0 ppb |
| 2014-05-15 | 6640-02869CH | 21.1 ppb |
| 2014-05-15 | 6641-02870CH | 28.4 ppb |
| 2014-05-15 | 6642-02871CH | 41.5 ppb |
| 2014-05-15 | 6643-02872CH | 26.0 ppb |
| 2014-05-15 | 6645-02873CH | 19.8 ppb |
| 2014-05-15 | 6646-02874CH | 23.5 ppb |
| 2014-05-15 | 6647-02875CH | 40.4 ppb |
| 2014-05-15 | 6648-02876CH | 34.0 ppb |
| 2014-08-26 | 12867-03013CH | 19.4 ppb |
| 2014-08-26 | 12868-03014CH | 25.3 ppb |
| 2014-08-26 | 12869-03015CH | 42.1 ppb |
| 2014-08-26 | 12870-03016CH | 22.5 ppb |
| 2014-08-26 | 12872-03017CH | 17.7 ppb |
| 2014-08-26 | 12873-03019CH | 20.8 ppb |
| 2014-08-26 | 12874-03018CH | 42.8 ppb |
| 2014-08-26 | 12875-03020CH | 31.0 ppb |
| 2014-11-25 | 18554-03121CH | 15.7 ppb |
| 2014-11-25 | 18555-03122CH | 22.9 ppb |
| 2014-11-25 | 18556-03123CH | 33.3 ppb |
| 2014-11-25 | 18557-03124CH | 18.8 ppb |
| 2014-11-25 | 18559-03125CH | 14.4 ppb |
| 2014-11-25 | 18560-03126CH | 17.8 ppb |
| 2014-11-25 | 18561-03127CH | 30.9 ppb |
| 2014-11-25 | 18562-03128CH | 23.9 ppb |
| 2015-02-18 | 1837-03174CH | 16.7 ppb |
| 2015-02-18 | 1834-03172CH | 18.9 ppb |
| 2015-02-18 | 1831-03169CH | 15.5 ppb |
| 2015-02-18 | 1832-03170CH | 19.4 ppb |
| 2015-02-18 | 1836-03173CH | 16.4 ppb |
| 2015-02-18 | 1833-03171CH | 28.1 ppb |
| 2015-02-18 | 1839-03176CH | 23.1 ppb |
| 2015-02-18 | 1838-03175CH | 29.1 ppb |
| 2015-05-22 | 7396-03235CH | 40.1 ppb |
| 2015-05-22 | 7395-03234CH | 25.5 ppb |
| 2015-05-22 | 7389-03229CH | 20.7 ppb |
| 2015-05-22 | 7390-03230CH | 37.8 ppb |
| 2015-05-22 | 7397-03236CH | 33.2 ppb |
| 2015-05-22 | 7394-03233CH | 21.3 ppb |
| 2015-05-22 | 7391-03231CH | 38.4 ppb |
| 2015-05-22 | 7392-03237CH | 22.5 ppb |
| 2015-08-19 | 12408-03344CH | 46.7 ppb |
| 2015-08-19 | 12415-03350CH | 54.2 ppb |
| 2015-08-19 | 12414-03349CH | 57.0 ppb |
| 2015-08-19 | 12409-03345CH | 55.7 ppb |
| 2015-08-19 | 12407-03343CH | 35.4 ppb |
| 2015-08-19 | 12413-03348CH | 39.5 ppb |
| 2015-08-19 | 12410-03346CH | 43.8 ppb |
| 2015-08-19 | 12412-03347CH | 31.4 ppb |
| 2015-11-18 | 17414-03426CH | 19.7 ppb |
| 2015-11-18 | 17408-03421CH | 17.5 ppb |
| 2015-11-18 | 17410-03423CH | 42.5 ppb |
| 2015-11-18 | 17413-03425CH | 14.7 ppb |
| 2015-11-18 | 17416-03428CH | 30.1 ppb |
| 2015-11-18 | 17415-03427CH | 41.1 ppb |
| 2015-11-18 | 17409-03422CH | 24.5 ppb |
| 2015-11-18 | 17411-03424CH | 24.4 ppb |
| 2016-02-17 | 2382-03483CH | 18.6 ppb |
| 2016-02-17 | 2383-03484CH | 23.2 ppb |
| 2016-02-17 | 2384-03485CH | 36.3 ppb |
| 2016-02-17 | 2385-03486CH | 22.4 ppb |
| 2016-02-17 | 2387-03487CH | 15.4 ppb |
| 2016-02-17 | 2388-03488CH | 19.9 ppb |
| 2016-02-17 | 2389-03489CH | 37.5 ppb |
| 2016-02-17 | 2390-03490CH | 28.9 ppb |
| 2016-05-19 | 7548-03552CH | 21.8 ppb |
| 2016-05-19 | 7549-03553CH | 26.2 ppb |
| 2016-05-19 | 7550-03554CH | 44.5 ppb |
| 2016-05-19 | 7551-03555CH | 22.7 ppb |
| 2016-05-19 | 7553-03556CH | 18.6 ppb |
| 2016-05-19 | 7554-03557CH | 21.3 ppb |
| 2016-05-19 | 7555-03558CH | 45.4 ppb |
| 2016-05-19 | 7556-03559CH | 30.1 ppb |
| 2016-08-18 | 12521-03642CH | 42.4 ppb |
| 2016-08-18 | 12522-03643CH | 55.0 ppb |
| 2016-08-18 | 12523-03644CH | 65.9 ppb |
| 2016-08-18 | 12524-03645CH | 51.0 ppb |
| 2016-08-18 | 12526-03646CH | 40.9 ppb |
| 2016-08-18 | 12527-03647CH | 46.4 ppb |
| 2016-08-18 | 12528-03648CH | 66.8 ppb |
| 2016-08-18 | 12529-03649CH | 60.2 ppb |
| 2016-11-28 | 17592-03706CH | 17.2 ppb |
| 2016-11-28 | 17593-03707CH | 23.5 ppb |
| 2016-11-28 | 17594-03708CH | 30.6 ppb |
| 2016-11-28 | 17595-03709CH | 19.8 ppb |
| 2016-11-28 | 17597-03710CH | 15.0 ppb |
| 2016-11-28 | 17598-03711CH | 18.6 ppb |
| 2016-11-28 | 17599-03712CH | 44.7 ppb |
| 2016-11-28 | 17600-03713CH | 25.1 ppb |
| 2017-02-17 | 1920-03779CH | 12.8 ppb |
| 2017-02-17 | 1921-03780CH | 18.7 ppb |
| 2017-02-17 | 1922-03781CH | 33.7 ppb |
| 2017-02-17 | 1923-03782CH | 16.0 ppb |
| 2017-02-17 | 1925-03783CH | 11.7 ppb |
| 2017-02-17 | 1926-03784CH | 29.0 ppb |
| 2017-02-17 | 1928-03785CH | 24.6 ppb |
| 2017-02-17 | 1927-03880CH | 29.0 ppb |
| 2017-05-10 | 5576-03833CH | 21.9 ppb |
| 2017-05-10 | 5577-03834CH | 29.7 ppb |
| 2017-05-10 | 5578-03835CH | 41.4 ppb |
| 2017-05-10 | 5579-03836CH | 28.1 ppb |
| 2017-05-10 | 5581-03837CH | 20.6 ppb |
| 2017-05-10 | 5582-03838CH | 23.3 ppb |
| 2017-05-10 | 5583-03839CH | 44.3 ppb |
| 2017-05-10 | 5584-03840CH | 32.8 ppb |
| 2017-08-16 | DBP 200474703 | 40.4 ppb |
| 2017-08-16 | DBP 200474704 | 38.9 ppb |
| 2017-08-16 | DBP 200474705 | 48.3 ppb |
| 2017-08-16 | DBP 200474706 | 54.5 ppb |
| 2017-08-16 | DBP 200474707 | 44.0 ppb |
| 2017-08-16 | DBP 200474708 | 64.2 ppb |
| 2017-08-16 | DBP 200474709 | 65.5 ppb |
| 2017-08-16 | DBP 200474710 | 62.2 ppb |
| 2017-11-15 | DBP 200482173 | 31.5 ppb |
| 2017-11-15 | DBP 200482174 | 27.6 ppb |
| 2017-11-15 | DBP 200482175 | 37.2 ppb |
| 2017-11-15 | DBP 200482176 | 42.8 ppb |
| 2017-11-15 | DBP 200482177 | 35.0 ppb |
| 2017-11-15 | DBP 200482178 | 65.2 ppb |
| 2017-11-15 | DBP 200482179 | 66.0 ppb |
| 2017-11-15 | DBP 200482180 | 52.1 ppb |
| 2017-11-15 | DBP 200482181 | 32.3 ppb |
| 2018-02-22 | DBP 200488580 | 23.1 ppb |
| 2018-02-22 | DBP 200488581 | 19.6 ppb |
| 2018-02-22 | DBP 200488582 | 29.0 ppb |
| 2018-02-22 | DBP 200488583 | 29.4 ppb |
| 2018-02-22 | DBP 200488584 | 25.1 ppb |
| 2018-02-22 | DBP 200488585 | 44.2 ppb |
| 2018-02-22 | DBP 200488586 | 45.3 ppb |
| 2018-02-22 | DBP 200488587 | 34.8 ppb |
| 2018-05-16 | DBP 200494888 | 27.7 ppb |
| 2018-05-16 | DBP 200494889 | 23.2 ppb |
| 2018-05-16 | DBP 200494890 | 30.9 ppb |
| 2018-05-16 | DBP 200494891 | 34.4 ppb |
| 2018-05-16 | DBP 200494892 | 29.1 ppb |
| 2018-05-16 | DBP 200494893 | 48.3 ppb |
| 2018-05-16 | DBP 200494894 | 46.4 ppb |
| 2018-05-16 | DBP 200494895 | 40.1 ppb |
| 2018-08-14 | DBP 200502300 | 49.0 ppb |
| 2018-08-14 | DBP 200502301 | 44.4 ppb |
| 2018-08-14 | DBP 200502302 | 57.3 ppb |
| 2018-08-14 | DBP 200502303 | 60.6 ppb |
| 2018-08-14 | DBP 200502304 | 52.4 ppb |
| 2018-08-14 | DBP 200502305 | 75.1 ppb |
| 2018-08-14 | DBP 200502306 | 71.5 ppb |
| 2018-08-14 | DBP 200502307 | 76.4 ppb |
| 2018-11-14 | DBP 200512645 | 33.1 ppb |
| 2018-11-14 | DBP 200512646 | 25.7 ppb |
| 2018-11-14 | DBP 200512647 | 37.5 ppb |
| 2018-11-14 | DBP 200512648 | 43.5 ppb |
| 2018-11-14 | DBP 200512649 | 35.3 ppb |
| 2018-11-14 | DBP 200512650 | 63.3 ppb |
| 2018-11-14 | DBP 200512651 | 59.5 ppb |
| 2018-11-14 | DBP 200512652 | 46.5 ppb |
| 2018-11-14 | DBP 200512654 | 33.2 ppb |
| 2019-02-20 | DBP 200522297 | 15.2 ppb |
| 2019-02-20 | DBP 200522298 | 14.0 ppb |
| 2019-02-20 | DBP 200522299 | 20.3 ppb |
| 2019-02-20 | DBP 200522300 | 25.3 ppb |
| 2019-02-20 | DBP 200522301 | 18.9 ppb |
| 2019-02-20 | DBP 200522302 | 36.4 ppb |
| 2019-02-20 | DBP 200522303 | 35.7 ppb |
| 2019-02-20 | DBP 200522304 | 23.6 ppb |
| 2019-05-16 | DBP 200532562 | 27.2 ppb |
| 2019-05-16 | DBP 200532563 | 22.5 ppb |
| 2019-05-16 | DBP 200532564 | 31.3 ppb |
| 2019-05-16 | DBP 200532565 | 35.1 ppb |
| 2019-05-16 | DBP 200532566 | 30.2 ppb |
| 2019-05-16 | DBP 200532567 | 54.4 ppb |
| 2019-05-16 | DBP 200532568 | 42.7 ppb |
| 2019-05-16 | DBP 200532569 | 38.2 ppb |
| 2019-08-20 | DBP 200545574 | 42.5 ppb |
| 2019-08-20 | DBP 200545575 | 42.0 ppb |
| 2019-08-20 | DBP 200545576 | 64.0 ppb |
| 2019-08-20 | DBP 200545577 | 73.7 ppb |
| 2019-08-20 | DBP 200545578 | 52.5 ppb |
| 2019-08-20 | DBP 200545579 | 79.3 ppb |
| 2019-08-20 | DBP 200545580 | 77.4 ppb |
| 2019-08-20 | DBP 200545581 | 80.4 ppb |
| 2019-11-21 | DBP 200557689 | 25.4 ppb |
| 2019-11-21 | DBP 200557690 | 22.0 ppb |
| 2019-11-21 | DBP 200557691 | 33.5 ppb |
| 2019-11-21 | DBP 200557692 | 34.5 ppb |
| 2019-11-21 | DBP 200557693 | 28.7 ppb |
| 2019-11-21 | DBP 200557694 | 56.2 ppb |
| 2019-11-21 | DBP 200557695 | 51.2 ppb |
| 2019-11-21 | DBP 200557696 | 34.9 ppb |