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EWG's Tap Water Database — 2021 UPDATE

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Total trihalomethanes (TTHMs)

Lees Summit

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.

 

100

Samples

0

Samples exceeding legal limit (MCL)

83

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20145.31 ppb2015ND - 18.9 ppb
20155.87 ppb1614ND - 16.5 ppb
20167.48 ppb16162.19 ppb - 16.8 ppb
20175.87 ppb1514ND - 10.4 ppb
20186.73 ppb1711ND - 15.3 ppb
20198.21 ppb1613ND - 18.1 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
2014-03-12AC198654.94 ppb
2014-03-12AC19866ND
2014-03-12AC19867ND
2014-03-12AC19868ND
2014-06-11AC2850918.5 ppb
2014-06-11AC2851018.9 ppb
2014-06-11AC285116.04 ppb
2014-06-11AC285125.83 ppb
2014-06-11AC285133.65 ppb
2014-06-11AC285143.84 ppb
2014-06-11AC285153.97 ppb
2014-06-11AC285163.80 ppb
2014-09-12AC355697.64 ppb
2014-09-12AC355707.49 ppb
2014-09-12AC355727.79 ppb
2014-09-12AC355716.89 ppb
2014-12-15AC394644.52 ppb
2014-12-15AC394652.34 ppb
2014-12-15AC39466ND
2014-12-15AC39467ND
2015-03-12AC435463.02 ppb
2015-03-12AC435452.50 ppb
2015-03-12AC435444.85 ppb
2015-03-12AC435473.47 ppb
2015-06-17AC511635.60 ppb
2015-06-17AC511646.28 ppb
2015-06-17AC511626.43 ppb
2015-06-17AC5116116.5 ppb
2015-09-15AC594817.13 ppb
2015-09-15AC594798.39 ppb
2015-09-15AC5947810.2 ppb
2015-09-15AC594806.54 ppb
2015-12-10AC63913ND
2015-12-10AC63912ND
2015-12-10AC6391110.3 ppb
2015-12-10AC639142.64 ppb
2016-03-08AC676132.19 ppb
2016-03-08AC676107.70 ppb
2016-03-08AC676113.19 ppb
2016-03-08AC676122.72 ppb
2016-06-09AC7481715.7 ppb
2016-06-09AC748155.34 ppb
2016-06-09AC7481611.2 ppb
2016-06-10AC7481416.8 ppb
2016-09-06AC8375510.00 ppb
2016-09-07AC837568.77 ppb
2016-09-07AC837588.89 ppb
2016-09-07AC837577.78 ppb
2016-12-08AC884193.76 ppb
2016-12-08AC884183.92 ppb
2016-12-08AC884168.87 ppb
2016-12-08AC884172.90 ppb
2017-03-13AC921084.56 ppb
2017-03-13AC921093.52 ppb
2017-03-13AC921079.45 ppb
2017-03-13AC921104.40 ppb
2017-06-07AC984058.39 ppb
2017-06-07AC984049.54 ppb
2017-06-07AC984069.02 ppb
2017-06-07AC9840310.4 ppb
2017-09-11AD064055.83 ppb
2017-09-11AD064046.57 ppb
2017-09-11AD064065.93 ppb
2017-09-11AD064075.87 ppb
2017-12-12AD10577ND
2017-12-12AD105752.25 ppb
2017-12-12AD105762.34 ppb
2018-01-19AD124264.03 ppb
2018-03-09AD16454ND
2018-03-09AD16453ND
2018-03-09AD164527.18 ppb
2018-03-09AD16455ND
2018-06-07AD2722913.8 ppb
2018-06-07AD2723011.8 ppb
2018-06-07AD2723112.9 ppb
2018-06-07AD2723212.0 ppb
2018-09-10AD328818.78 ppb
2018-09-10AD3288015.3 ppb
2018-09-10AD328829.95 ppb
2018-09-10AD3288310.8 ppb
2018-12-12AD36751ND
2018-12-12AD36750ND
2018-12-12AD36749ND
2018-12-12AD367487.85 ppb
2019-03-12AD404795.61 ppb
2019-03-12AD40480ND
2019-03-12AD40481ND
2019-03-12AD40482ND
2019-06-10AD4903513.3 ppb
2019-06-10AD4903418.1 ppb
2019-06-10AD4903614.1 ppb
2019-06-10AD4903710.8 ppb
2019-09-11AD5514113.3 ppb
2019-09-11AD5514410.4 ppb
2019-09-11AD5514310.1 ppb
2019-09-11AD551428.66 ppb
2019-12-03AD5905911.5 ppb
2019-12-03AD590604.84 ppb
2019-12-03AD590615.54 ppb
2019-12-03AD590625.05 ppb