Total trihalomethanes (TTHMs)
Yonkers City
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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2013 | N/A | 0 | 0 | N/A |
2014 | 27.3 ppb | 32 | 32 | 14.0 ppb - 44.0 ppb |
2015 | 26.0 ppb | 16 | 16 | 15.0 ppb - 40.0 ppb |
2016 | 32.3 ppb | 32 | 32 | 16.0 ppb - 53.0 ppb |
2017 | 31.6 ppb | 32 | 32 | 15.0 ppb - 50.0 ppb |
2018 | 32.4 ppb | 32 | 32 | 16.0 ppb - 51.0 ppb |
2019 | 31.0 ppb | 33 | 32 | ND - 48.0 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 |
---|---|---|
2014-02-04 | 201402050179DBP | 17.0 ppb |
2014-02-04 | 201402050182DBP | 14.0 ppb |
2014-02-04 | 201402050177DBP | 29.0 ppb |
2014-02-04 | 201402050176DBP | 21.0 ppb |
2014-02-04 | 201402050175DBP | 25.0 ppb |
2014-02-04 | 201402050178DBP | 27.0 ppb |
2014-02-04 | 201402050181DBP | 18.0 ppb |
2014-02-04 | 201402050180DBP | 21.0 ppb |
2014-05-08 | 201405090632DBP | 29.0 ppb |
2014-05-08 | 201405090631DBP | 34.0 ppb |
2014-05-08 | 201405090633DBP | 28.0 ppb |
2014-05-08 | 201405090628DBP | 40.0 ppb |
2014-05-08 | 201405090630DBP | 31.0 ppb |
2014-05-08 | 201405090626DBP | 36.0 ppb |
2014-05-08 | 201405090627DBP | 29.0 ppb |
2014-05-08 | 201405090629DBP | 44.0 ppb |
2014-08-07 | 201408080285DBP | 17.0 ppb |
2014-08-07 | 201408080281DBP | 15.0 ppb |
2014-08-07 | 201408080284DBP | 23.0 ppb |
2014-08-07 | 201408080287DBP | 23.0 ppb |
2014-08-07 | 201408080282DBP | 32.0 ppb |
2014-08-07 | 201408080283DBP | 26.0 ppb |
2014-08-07 | 201408080280DBP | 42.0 ppb |
2014-08-07 | 201408080286DBP | 28.0 ppb |
2014-11-06 | 201411070599 DBP | 17.0 ppb |
2014-11-06 | 201411070595 DBP | 34.0 ppb |
2014-11-06 | 201411070600 DBP | 28.0 ppb |
2014-11-06 | 201411070601 DBP | 22.0 ppb |
2014-11-06 | 201411070597 DBP | 37.0 ppb |
2014-11-06 | 201411070602 DBP | 27.0 ppb |
2014-11-06 | 201411070596 DBP | 28.0 ppb |
2014-11-06 | 201411070598 DBP | 30.0 ppb |
2015-02-05 | 201502060181 DBP | 21.0 ppb |
2015-02-05 | 201502060186 DBP | 19.0 ppb |
2015-02-05 | 201502060185 DBP | 20.0 ppb |
2015-02-05 | 201502060187 DBP | 15.0 ppb |
2015-02-05 | 201502060180 DBP | 26.0 ppb |
2015-02-05 | 201502060184 DBP | 16.0 ppb |
2015-02-05 | 201502060183 DBP | 21.0 ppb |
2015-02-05 | 201502060182 DBP | 29.0 ppb |
2015-05-04 | 201505120255 DBP | 40.0 ppb |
2015-05-04 | 201505120256 DBP | 27.0 ppb |
2015-05-04 | 201505120257 DBP | 36.0 ppb |
2015-05-08 | 201505120262 DBP | 25.0 ppb |
2015-05-08 | 201505120260 DBP | 31.0 ppb |
2015-05-08 | 201505120258 DBP | 39.0 ppb |
2015-05-08 | 201505120259 DBP | 23.0 ppb |
2015-05-08 | 201505120261 DBP | 28.0 ppb |
2016-02-04 | 201602050215 DBP | 30.0 ppb |
2016-02-04 | 201602050216 DBP | 21.0 ppb |
2016-02-04 | 201602050222 DBP | 18.0 ppb |
2016-02-04 | 201602050218 DBP | 31.0 ppb |
2016-02-04 | 201602050219 DBP | 23.0 ppb |
2016-02-04 | 201602050221 DBP | 16.0 ppb |
2016-02-04 | 201602050220 DBP | 19.0 ppb |
2016-02-04 | 201602050217 DBP | 31.0 ppb |
2016-05-05 | 201605060282 DBP | 45.0 ppb |
2016-05-05 | 201605060281 DBP | 46.0 ppb |
2016-05-05 | 201605060283 DBP | 27.0 ppb |
2016-05-05 | 201605060280 DBP | 29.0 ppb |
2016-05-05 | 201605060286 DBP | 27.0 ppb |
2016-05-05 | 201605060284 DBP | 35.0 ppb |
2016-05-05 | 201605060285 DBP | 27.0 ppb |
2016-05-05 | 201605060279 DBP | 45.0 ppb |
2016-08-04 | 20160805074 DBP | 30.0 ppb |
2016-08-04 | 201608050759 DBP | 46.0 ppb |
2016-08-04 | 201608050763 DBP | 42.0 ppb |
2016-08-04 | 201608050765 DBP | 41.0 ppb |
2016-08-04 | 201608050766 DBP | 41.0 ppb |
2016-08-04 | 201608050761 DBP | 47.0 ppb |
2016-08-04 | 201608050762 DBP | 53.0 ppb |
2016-08-04 | 201608050760 DBP | 31.0 ppb |
2016-11-04 | 201611080639 DBP | 26.0 ppb |
2016-11-04 | 201611080635 DBP | 39.0 ppb |
2016-11-04 | 201611080636 DBP | 25.0 ppb |
2016-11-04 | 201611080637 DBP | 34.0 ppb |
2016-11-04 | 201611080633 DBP | 22.0 ppb |
2016-11-04 | 201611080638 DBP | 25.0 ppb |
2016-11-04 | 201611080634 DBP | 40.0 ppb |
2016-11-04 | 201611080632 DBP | 20.0 ppb |
2017-02-08 | 201702091187 DBP | 20.0 ppb |
2017-02-08 | 201702091189 DBP | 21.0 ppb |
2017-02-08 | 201702091186 DBP | 33.0 ppb |
2017-02-08 | 201702091190 DBP | 18.0 ppb |
2017-02-08 | 201702091188 DBP | 21.0 ppb |
2017-02-08 | 201702091184 DBP | 15.0 ppb |
2017-02-08 | 201702091185 DBP | 30.0 ppb |
2017-02-08 | 201702091183 DBP | 23.0 ppb |
2017-06-01 | 201706020312-DBP | 50.0 ppb |
2017-06-01 | 201706020315-DBP | 48.0 ppb |
2017-06-01 | 201706020318-DBP | 44.0 ppb |
2017-06-01 | 201706020317-DBP | 38.0 ppb |
2017-06-01 | 201706020316-DBP | 27.0 ppb |
2017-06-01 | 201706020314-DBP | 48.0 ppb |
2017-06-01 | 201706020313-DBP | 32.0 ppb |
2017-06-01 | 201706020319-DBP | 37.0 ppb |
2017-08-07 | 201708081020-DBP | 31.0 ppb |
2017-08-07 | 201708081014-DBP | 24.0 ppb |
2017-08-07 | 201708081016-DBP | 44.0 ppb |
2017-08-07 | 201708081013-DBP | 49.0 ppb |
2017-08-07 | 201708081019-DBP | 35.0 ppb |
2017-08-07 | 201708081017-DBP | 26.0 ppb |
2017-08-07 | 201708081018-DBP | 19.0 ppb |
2017-08-07 | 201708081015-DBP | 44.0 ppb |
2017-11-09 | 201711100260-DBP | 31.0 ppb |
2017-11-09 | 201711100256-DBP | 23.0 ppb |
2017-11-09 | 201711100258-DBP | 36.0 ppb |
2017-11-09 | 201711100257-DBP | 36.0 ppb |
2017-11-09 | 201711100261-DBP | 24.0 ppb |
2017-11-09 | 201711100262-DBP | 24.0 ppb |
2017-11-09 | 201711100255-DBP | 32.0 ppb |
2017-11-09 | 201711100259-DBP | 29.0 ppb |
2018-02-13 | 201802140882-DBP | 16.0 ppb |
2018-02-13 | 201802140883-DBP | 34.0 ppb |
2018-02-13 | 201802140886-DBP | 21.0 ppb |
2018-02-13 | 201802140887-DBP | 20.0 ppb |
2018-02-13 | 201802140884-DBP | 32.0 ppb |
2018-02-13 | 201802140885-DBP | 19.0 ppb |
2018-02-13 | 201802140888-DBP | 19.0 ppb |
2018-02-13 | 201802140881-DBP | 24.0 ppb |
2018-05-14 | 201805150321-DBP | 26.0 ppb |
2018-05-14 | 201805150314-DBP | 36.0 ppb |
2018-05-14 | 201805150318-DBP | 27.0 ppb |
2018-05-14 | 201805150320-DBP | 28.0 ppb |
2018-05-14 | 201805150316-DBP | 37.0 ppb |
2018-05-14 | 201805150315-DBP | 30.0 ppb |
2018-05-14 | 201805150319-DBP | 38.0 ppb |
2018-05-14 | 201805150317-DBP | 44.0 ppb |
2018-08-06 | 201808080566-DBP | 35.0 ppb |
2018-08-06 | 201808080567-DBP | 34.0 ppb |
2018-08-06 | 201808080568-DBP | 29.0 ppb |
2018-08-06 | 201808080564-DBP | 40.0 ppb |
2018-08-06 | 201808080563-DBP | 37.0 ppb |
2018-08-06 | 201808080561-DBP | 51.0 ppb |
2018-08-06 | 201808080562-DBP | 29.0 ppb |
2018-08-06 | 201808080565-DBP | 29.0 ppb |
2018-11-07 | 201811090237-DBP | 33.0 ppb |
2018-11-07 | 201811090241-DBP | 38.0 ppb |
2018-11-07 | 201811090238-DBP | 50.0 ppb |
2018-11-07 | 201811090243-DBP | 29.0 ppb |
2018-11-07 | 201811090242-DBP | 31.0 ppb |
2018-11-07 | 201811090236-DBP | 42.0 ppb |
2018-11-07 | 201811090239-DBP | 47.0 ppb |
2018-11-07 | 201811090240-DBP | 33.0 ppb |
2019-02-05 | 7078668001-DBP2 | 36.0 ppb |
2019-02-05 | 7078668005-DBP2 | 24.0 ppb |
2019-02-05 | 7078668003-DBP2 | 37.0 ppb |
2019-02-05 | 7078668007-DBP2 | 22.0 ppb |
2019-02-05 | 7078668002-DBP2 | 30.0 ppb |
2019-02-05 | 7078668004-DBP2 | 30.0 ppb |
2019-02-05 | 7078668006-DBP2 | 25.0 ppb |
2019-02-05 | 7078668008-DBP2 | 22.0 ppb |
2019-02-05 | 201902060648-DBP | ND |
2019-05-02 | 201905030248-DBP | 28.0 ppb |
2019-05-02 | 201905030247-DBP | 24.0 ppb |
2019-05-02 | 201905030243-DBP | 44.0 ppb |
2019-05-02 | 201905030244-DBP | 29.0 ppb |
2019-05-02 | 201905030245-DBP | 40.0 ppb |
2019-05-02 | 201905030246-DBP | 37.0 ppb |
2019-05-02 | 201905030250-DBP | 28.0 ppb |
2019-05-02 | 201205030249-DBP | 26.0 ppb |
2019-08-06 | 201908070685-DBP | 30.0 ppb |
2019-08-06 | 201908070686-DBP | 34.0 ppb |
2019-08-06 | 201908070680-DBP | 45.0 ppb |
2019-08-06 | 201908070684-DBP | 31.0 ppb |
2019-08-06 | 201908070681-DBP | 28.0 ppb |
2019-08-06 | 201908070682-DBP | 39.0 ppb |
2019-08-06 | 201908070687-DBP | 30.0 ppb |
2019-08-06 | 201908070683-DBP | 48.0 ppb |
2019-11-06 | 70111070001 DBP2 | 34.7 ppb |
2019-11-06 | 70111070007 DBP2 | 26.0 ppb |
2019-11-06 | 70114414001 DBP2 | 35.6 ppb |
2019-11-06 | 7011441402 DBP2 | 40.4 ppb |
2019-11-06 | 70114414003 DBP2 | 42.4 ppb |
2019-11-06 | 70111070006 DBP2 | 28.4 ppb |
2019-11-06 | 70111070005 DBP2 | 25.0 ppb |
2019-11-06 | 70111070008 DBP2 | 25.1 ppb |