Total trihalomethanes (TTHMs)
Dewitt WDS - North
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 | 38.9 ppb | 16 | 16 | 26.0 ppb - 52.0 ppb |
| 2015 | 35.5 ppb | 16 | 16 | 19.0 ppb - 58.0 ppb |
| 2016 | 40.8 ppb | 16 | 16 | 21.0 ppb - 61.0 ppb |
| 2017 | 54.6 ppb | 12 | 12 | 38.0 ppb - 85.0 ppb |
| 2018 | 38.7 ppb | 16 | 16 | 28.0 ppb - 53.0 ppb |
| 2019 | 47.3 ppb | 16 | 16 | 35.0 ppb - 68.0 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 |
|---|---|---|
| 2014-02-13 | 1Q2014 RUSSELL L | 27.0 ppb |
| 2014-02-13 | 1Q2014 FLY RD | 43.0 ppb |
| 2014-02-13 | 1Q2014 ALMONT DR | 31.0 ppb |
| 2014-02-13 | 1Q2014 BADGELY R | 26.0 ppb |
| 2014-05-13 | 2Q2014 FLY RD | 33.0 ppb |
| 2014-05-13 | 2Q2014 RUSSELL L | 46.0 ppb |
| 2014-05-13 | 2Q2014 ALMONT DR | 43.0 ppb |
| 2014-05-13 | 2Q2014 BADGELY R | 36.0 ppb |
| 2014-08-13 | 3Q2014 ALMONT DR | 51.0 ppb |
| 2014-08-13 | 3Q2014 BADGELY R | 52.0 ppb |
| 2014-08-13 | 3Q2014 FLY RD | 39.0 ppb |
| 2014-08-13 | 3Q2014 RUSSELL L | 38.0 ppb |
| 2014-11-13 | 4Q2014 RUSSELL L | 34.0 ppb |
| 2014-11-13 | 4Q2014 FLY RD | 34.0 ppb |
| 2014-11-13 | 4Q2014 BADGELY R | 41.0 ppb |
| 2014-11-13 | 4Q2014 ALMONT DR | 49.0 ppb |
| 2015-02-11 | 1Q2015 FLY RD | 19.0 ppb |
| 2015-02-11 | 1Q2015 ALMONT DR | 21.6 ppb |
| 2015-02-11 | 1Q2015 RUSSELL L | 21.7 ppb |
| 2015-02-11 | 1Q2015 BADGELY R | 36.0 ppb |
| 2015-05-14 | 2Q2015 RUSSELL L | 25.0 ppb |
| 2015-05-14 | 2Q2015 FLY RD | 22.0 ppb |
| 2015-05-14 | 2Q2015 ALMONT DR | 27.0 ppb |
| 2015-05-14 | 2Q2015 BADGELY R | 29.0 ppb |
| 2015-08-13 | 3Q2015 BADGELY R | 57.0 ppb |
| 2015-08-13 | 3Q2015 ALMONT DR | 43.0 ppb |
| 2015-08-13 | 3Q2015 RUSSELL L | 44.0 ppb |
| 2015-08-13 | 3Q2015 FLY RD | 36.0 ppb |
| 2015-11-09 | 4Q2015 RUSSELL L | 40.0 ppb |
| 2015-11-09 | 4Q2015 BADGELY R | 58.0 ppb |
| 2015-11-09 | 4Q2015 ALMONT DR | 42.0 ppb |
| 2015-11-09 | 4Q2015 FLY RD | 46.0 ppb |
| 2016-02-12 | 1Q2016 ALMONT DR | 24.0 ppb |
| 2016-02-12 | 1Q2016 RUSSELL L | 22.0 ppb |
| 2016-02-12 | 1Q2016 FLY RD | 21.0 ppb |
| 2016-02-12 | 1Q2016 BADGELY R | 33.0 ppb |
| 2016-05-17 | 2Q2016 FLY RD | 29.0 ppb |
| 2016-05-17 | 2Q2016 BADGELY R | 41.0 ppb |
| 2016-05-17 | 2Q2016 RUSSELL L | 35.0 ppb |
| 2016-05-17 | 2Q2016 ALMONT DR | 33.0 ppb |
| 2016-08-10 | 3Q2016 BADGELY R | 56.0 ppb |
| 2016-08-10 | 3Q2016 RUSSELL L | 43.0 ppb |
| 2016-08-10 | 3Q2016 FLY RD | 52.0 ppb |
| 2016-08-10 | 3Q2016 ALMONT DR | 48.0 ppb |
| 2016-11-08 | 4Q2016 BADGELY R | 61.0 ppb |
| 2016-11-08 | 4Q2016 FLY RD | 51.0 ppb |
| 2016-11-08 | 4Q2016 ALMONT DR | 45.0 ppb |
| 2016-11-08 | 4Q2016 RUSSELL L | 59.0 ppb |
| 2017-05-10 | 2Q2017 ALMONT DR | 50.0 ppb |
| 2017-05-10 | 2Q2017 FLY RD | 54.0 ppb |
| 2017-05-10 | 2Q2017 BADGELY R | 59.0 ppb |
| 2017-05-10 | 2Q2017 RUSSELL L | 47.0 ppb |
| 2017-08-09 | 3Q2017 RUSSELL L | 63.0 ppb |
| 2017-08-09 | 3Q2017 BADGELY R | 85.0 ppb |
| 2017-08-09 | 3Q2017 FLY RD | 71.0 ppb |
| 2017-08-09 | 3Q2017 ALMONT DR | 64.0 ppb |
| 2017-11-07 | 4Q2017 ALMONT DR | 40.0 ppb |
| 2017-11-07 | 4Q2017 BADGELY R | 46.0 ppb |
| 2017-11-07 | 4Q2017 RUSSELL L | 38.0 ppb |
| 2017-11-07 | 4Q2017 FLY RD | 38.0 ppb |
| 2018-02-15 | 1Q2018 ALMONT DR | 29.0 ppb |
| 2018-02-15 | 1Q2018 FLY RD | 34.0 ppb |
| 2018-02-15 | 1Q2018 RUSSELL L | 28.0 ppb |
| 2018-02-15 | 1Q2018 BADGLEY R | 34.0 ppb |
| 2018-05-10 | 2Q2018 FLY RD | 43.0 ppb |
| 2018-05-10 | 2Q2018 RUSSELL L | 42.0 ppb |
| 2018-05-10 | 2Q2018 ALMONT DR | 35.0 ppb |
| 2018-05-10 | 2Q2018 BADGLEY R | 51.0 ppb |
| 2018-08-14 | 3Q2018 RUSSELL L | 41.0 ppb |
| 2018-08-14 | 3Q2018 FLY RD | 43.0 ppb |
| 2018-08-14 | 3Q2018 ALMONT DR | 53.0 ppb |
| 2018-08-14 | 3Q2018 BADGLEY R | 52.0 ppb |
| 2018-11-07 | 4Q2018 FLY RD | 42.0 ppb |
| 2018-11-07 | 4Q2018 ALMONT DR | 30.0 ppb |
| 2018-11-07 | 4Q2018 RUSSELL L | 30.0 ppb |
| 2018-11-07 | 4Q2018 BADGLEY R | 32.0 ppb |
| 2019-02-14 | 1Q2019 ALMONT DR | 41.0 ppb |
| 2019-02-14 | 1Q2019 FLY RD | 43.0 ppb |
| 2019-02-14 | 1Q2019 RUSSELL L | 39.0 ppb |
| 2019-02-14 | 1Q2019 BADGLEY R | 39.0 ppb |
| 2019-05-10 | 2Q2019 RUSSELL L | 44.0 ppb |
| 2019-05-10 | 2Q2019 BADGLEY R | 50.0 ppb |
| 2019-05-10 | 2Q2019 FLY RD | 53.0 ppb |
| 2019-05-10 | 2Q2019 ALMONT DR | 44.0 ppb |
| 2019-08-13 | 3Q2019 FLY RD | 59.0 ppb |
| 2019-08-13 | 3Q2019 ALMONT DR | 53.0 ppb |
| 2019-08-13 | 3Q2019 RUSSELL L | 52.0 ppb |
| 2019-08-13 | 3Q2019 BADGLEY R | 68.0 ppb |
| 2019-11-06 | 4Q2019 BADGLEY R | 52.0 ppb |
| 2019-11-06 | 4Q2019 ALMONT DR | 35.0 ppb |
| 2019-11-06 | 4Q2019 FLY RD | 48.0 ppb |
| 2019-11-06 | 4Q2019 RUSSELL L | 36.0 ppb |