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EWG's Tap Water Database — 2019 UPDATE

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Total trihalomethanes (TTHMs)

Jordan Valley Water Conservancy District

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.

 

243

Samples

19

Samples exceeding legal limit (MCL)

219

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201225.1 ppb5548ND - 63.5 ppb
201320.0 ppb2820ND - 43.0 ppb
201432.0 ppb3633ND - 84.5 ppb
201551.6 ppb4543ND - 103.0 ppb
201640.0 ppb4443ND - 113.0 ppb
201737.1 ppb3532ND - 87.5 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 Result
2012-01-042.70 ppb
2012-01-0910.5 ppb
2012-01-099.60 ppb
2012-01-099.67 ppb
2012-01-099.21 ppb
2012-01-096.81 ppb
2012-01-093.42 ppb
2012-01-0928.9 ppb
2012-01-095.40 ppb
2012-01-096.95 ppb
2012-01-094.84 ppb
2012-02-0663.5 ppb
2012-02-062.72 ppb
2012-02-062.52 ppb
2012-02-06ND
2012-02-0738.3 ppb
2012-02-07ND
2012-02-07ND
2012-02-0742.6 ppb
2012-02-0730.7 ppb
2012-02-07ND
2012-03-0522.5 ppb
2012-03-059.20 ppb
2012-03-0516.7 ppb
2012-03-0547.9 ppb
2012-03-0544.5 ppb
2012-03-0542.0 ppb
2012-03-0541.8 ppb
2012-03-0545.5 ppb
2012-04-0926.2 ppb
2012-04-0961.3 ppb
2012-04-0942.5 ppb
2012-04-0931.9 ppb
2012-04-0949.8 ppb
2012-04-0938.1 ppb
2012-04-09ND
2012-04-0928.9 ppb
2012-06-27ND
2012-07-0915.8 ppb
2012-07-0942.2 ppb
2012-07-0928.6 ppb
2012-07-0935.4 ppb
2012-07-0946.0 ppb
2012-07-0928.8 ppb
2012-07-0938.7 ppb
2012-07-0941.8 ppb
2012-07-18ND
2012-10-1534.9 ppb
2012-10-1531.8 ppb
2012-10-1530.2 ppb
2012-10-1543.7 ppb
2012-10-1533.7 ppb
2012-10-1537.7 ppb
2012-10-1529.7 ppb
2012-10-1535.3 ppb
2013-03-0610.7 ppb
2013-06-26ND
2013-07-17ND
2013-07-1735.8 ppb
2013-07-170.764 ppb
2013-07-1737.6 ppb
2013-07-1725.6 ppb
2013-07-1730.6 ppb
2013-07-1736.7 ppb
2013-07-178.18 ppb
2013-08-29ND
2013-10-0741.5 ppb
2013-10-07ND
2013-10-07ND
2013-10-0729.6 ppb
2013-10-0714.5 ppb
2013-10-0733.6 ppb
2013-10-0724.3 ppb
2013-10-0743.0 ppb
2013-10-0741.5 ppb
2013-10-07ND
2013-10-0724.3 ppb
2013-10-0743.0 ppb
2013-10-07ND
2013-10-0714.5 ppb
2013-10-0729.6 ppb
2013-10-0733.6 ppb
2013-10-29ND
2014-01-02ND
2014-01-0620.5 ppb
2014-01-0612.6 ppb
2014-01-060.598 ppb
2014-01-0620.7 ppb
2014-01-06ND
2014-01-0621.8 ppb
2014-01-0722.9 ppb
2014-01-0721.3 ppb
2014-04-0722.8 ppb
2014-04-0746.4 ppb
2014-04-0727.7 ppb
2014-04-0731.0 ppb
2014-04-0742.8 ppb
2014-04-0734.6 ppb
2014-04-0830.8 ppb
2014-04-0832.6 ppb
2014-07-0721.9 ppb
2014-07-0730.8 ppb
2014-07-0730.8 ppb
2014-07-0734.5 ppb
2014-07-0718.0 ppb
2014-07-0732.0 ppb
2014-07-0718.4 ppb
2014-07-0734.5 ppb
2014-07-0724.8 ppb
2014-07-0724.6 ppb
2014-07-15ND
2014-10-0644.3 ppb
2014-10-0665.7 ppb
2014-10-0648.7 ppb
2014-10-0684.5 ppb
2014-10-0667.7 ppb
2014-10-0675.6 ppb
2014-10-0647.9 ppb
2014-10-0658.5 ppb
2015-01-050.764 ppb
2015-01-0549.6 ppb
2015-01-0544.0 ppb
2015-01-0540.3 ppb
2015-01-0547.1 ppb
2015-01-0557.2 ppb
2015-01-050.504 ppb
2015-01-0538.8 ppb
2015-01-13ND
2015-01-15ND
2015-02-180.500 ppb
2015-04-061.55 ppb
2015-04-0648.8 ppb
2015-04-0649.2 ppb
2015-04-0639.0 ppb
2015-04-0649.7 ppb
2015-04-0636.9 ppb
2015-04-0634.1 ppb
2015-04-0738.1 ppb
2015-07-0634.9 ppb
2015-07-0633.2 ppb
2015-07-0628.4 ppb
2015-07-0643.9 ppb
2015-07-0620.6 ppb
2015-07-0642.6 ppb
2015-07-0630.1 ppb
2015-07-0641.5 ppb
2015-10-0597.0 ppb
2015-10-0581.5 ppb
2015-10-05103.0 ppb
2015-10-0572.2 ppb
2015-10-0585.1 ppb
2015-10-0565.1 ppb
2015-10-0597.4 ppb
2015-10-0582.5 ppb
2015-10-0597.0 ppb
2015-10-0581.5 ppb
2015-10-05103.0 ppb
2015-10-0565.1 ppb
2015-10-0551.6 ppb
2015-10-0597.4 ppb
2015-10-0582.5 ppb
2015-10-0551.0 ppb
2015-10-0572.2 ppb
2015-10-0585.1 ppb
2016-01-0414.6 ppb
2016-01-0424.8 ppb
2016-01-0419.8 ppb
2016-01-0426.9 ppb
2016-01-0440.6 ppb
2016-01-0430.6 ppb
2016-01-0419.0 ppb
2016-01-0425.1 ppb
2016-01-0412.1 ppb
2016-01-0414.6 ppb
2016-01-0424.8 ppb
2016-01-0419.8 ppb
2016-01-0415.2 ppb
2016-01-0426.9 ppb
2016-01-0440.6 ppb
2016-01-0430.6 ppb
2016-01-0419.0 ppb
2016-01-0425.1 ppb
2016-03-2217.7 ppb
2016-04-0417.3 ppb
2016-04-0432.4 ppb
2016-04-0433.3 ppb
2016-04-0441.1 ppb
2016-04-0426.1 ppb
2016-04-0435.4 ppb
2016-04-0428.1 ppb
2016-04-0443.8 ppb
2016-07-0750.1 ppb
2016-07-0734.9 ppb
2016-07-0715.7 ppb
2016-07-0737.2 ppb
2016-07-0760.5 ppb
2016-07-0757.2 ppb
2016-07-0758.9 ppb
2016-07-0753.4 ppb
2016-07-14ND
2016-10-03112.0 ppb
2016-10-0395.2 ppb
2016-10-03113.0 ppb
2016-10-0367.8 ppb
2016-10-0388.5 ppb
2016-10-0374.0 ppb
2016-10-0380.0 ppb
2016-10-0355.0 ppb
2017-01-0345.0 ppb
2017-01-0333.4 ppb
2017-01-0331.5 ppb
2017-01-0334.0 ppb
2017-01-037.42 ppb
2017-01-0310.00 ppb
2017-01-037.27 ppb
2017-01-0341.2 ppb
2017-01-04ND
2017-01-1845.1 ppb
2017-04-0344.8 ppb
2017-04-035.46 ppb
2017-04-032.21 ppb
2017-04-0357.3 ppb
2017-04-0328.2 ppb
2017-04-0348.6 ppb
2017-04-0352.2 ppb
2017-04-03ND
2017-07-0543.8 ppb
2017-07-0550.5 ppb
2017-07-0518.3 ppb
2017-07-0559.9 ppb
2017-07-0536.0 ppb
2017-07-0558.6 ppb
2017-07-0553.6 ppb
2017-07-0554.0 ppb
2017-08-14ND
2017-10-0255.8 ppb
2017-10-0242.0 ppb
2017-10-0287.5 ppb
2017-10-0243.8 ppb
2017-10-0282.0 ppb
2017-10-0235.4 ppb
2017-10-0243.9 ppb
2017-10-0239.9 ppb