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EWG's Tap Water Database — 2019 UPDATE

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Total trihalomethanes (TTHMs)

City of Puyallup

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.

 

189

Samples

0

Samples exceeding legal limit (MCL)

116

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20123.79 ppb2916ND - 38.8 ppb
20134.56 ppb2516ND - 29.4 ppb
20143.36 ppb3819ND - 25.0 ppb
20154.09 ppb3223ND - 30.0 ppb
20164.35 ppb3222ND - 35.9 ppb
20173.49 ppb3320ND - 26.1 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
2012-02-0271188ND
2012-02-02711857.20 ppb
2012-02-0271187ND
2012-02-02711891.50 ppb
2012-02-02711862.90 ppb
2012-05-2471482ND
2012-05-2471483ND
2012-05-24714841.10 ppb
2012-05-2471480ND
2012-05-247147938.8 ppb
2012-05-2471481ND
2012-05-24714782.20 ppb
2012-05-24714772.20 ppb
2012-08-0671694ND
2012-08-0771698ND
2012-08-07716921.000 ppb
2012-08-0771693ND
2012-08-07716951.70 ppb
2012-08-077169619.0 ppb
2012-08-07716971.30 ppb
2012-08-0771691ND
2012-11-14721322.40 ppb
2012-11-14721360.300 ppb
2012-11-1472134ND
2012-11-14721313.80 ppb
2012-11-1472130ND
2012-11-1472133ND
2012-11-147213711.0 ppb
2012-11-147213513.6 ppb
2013-03-21723554.60 ppb
2013-03-2172358ND
2013-03-2172361ND
2013-03-21723590.300 ppb
2013-03-21723571.80 ppb
2013-03-2172360ND
2013-03-21723560.400 ppb
2013-03-217235429.4 ppb
2013-06-0372504ND
2013-08-0672727ND
2013-08-067273415.8 ppb
2013-08-0672730ND
2013-08-06727330.700 ppb
2013-08-0672728ND
2013-08-06727314.40 ppb
2013-08-06727292.50 ppb
2013-08-06727322.30 ppb
2013-11-21732202.20 ppb
2013-11-2173224ND
2013-11-21732225.80 ppb
2013-11-21732211.70 ppb
2013-11-217322527.8 ppb
2013-11-2173223ND
2013-11-217321811.9 ppb
2013-11-21732192.40 ppb
2014-02-11733280.300 ppb
2014-02-1173330ND
2014-02-117332612.8 ppb
2014-02-11733273.20 ppb
2014-02-1173331ND
2014-02-11733240.300 ppb
2014-02-1173329ND
2014-02-11733252.60 ppb
2014-05-06735153.90 ppb
2014-05-0673518ND
2014-05-06735211.70 ppb
2014-05-06735160.600 ppb
2014-05-0673514ND
2014-05-0673517ND
2014-05-06735197.40 ppb
2014-05-06735201.80 ppb
2014-07-0873733ND
2014-07-0873732ND
2014-07-0873731ND
2014-07-0973750ND
2014-07-09737521.60 ppb
2014-07-0973751ND
2014-08-0873950ND
2014-08-08739511.90 ppb
2014-08-0873948ND
2014-08-0873955ND
2014-08-08739542.30 ppb
2014-08-0873949ND
2014-08-087395211.7 ppb
2014-08-087395325.0 ppb
2014-11-1774521ND
2014-11-17745205.00 ppb
2014-11-17745174.60 ppb
2014-11-177451419.6 ppb
2014-11-177451921.4 ppb
2014-11-1774518ND
2014-11-1774515ND
2014-11-1774516ND
2015-02-1074752ND
2015-02-10747491.90 ppb
2015-02-10747502.60 ppb
2015-02-10747472.60 ppb
2015-02-10747533.80 ppb
2015-02-1074751ND
2015-02-1074746ND
2015-02-107474830.0 ppb
2015-05-0774983ND
2015-05-07749812.00 ppb
2015-05-07749774.30 ppb
2015-05-07749804.40 ppb
2015-05-07749821.70 ppb
2015-05-07749780.900 ppb
2015-05-0774979ND
2015-05-077497615.7 ppb
2015-08-0575262ND
2015-08-05752611.80 ppb
2015-08-05752575.10 ppb
2015-08-05752634.80 ppb
2015-08-05752591.50 ppb
2015-08-0575260ND
2015-08-0575258ND
2015-08-057525614.0 ppb
2015-11-1075671ND
2015-11-10756702.10 ppb
2015-11-10756755.10 ppb
2015-11-10756742.60 ppb
2015-11-10756680.600 ppb
2015-11-10756732.40 ppb
2015-11-10756724.70 ppb
2015-11-107566916.2 ppb
2016-02-02ND
2016-02-02ND
2016-02-023.30 ppb
2016-02-021.90 ppb
2016-02-02ND
2016-02-021.10 ppb
2016-02-021.90 ppb
2016-02-0220.8 ppb
2016-05-045.60 ppb
2016-05-044.00 ppb
2016-05-042.00 ppb
2016-05-045.00 ppb
2016-05-04ND
2016-05-043.50 ppb
2016-05-041.000 ppb
2016-05-04ND
2016-08-09ND
2016-08-090.600 ppb
2016-08-0935.9 ppb
2016-08-094.60 ppb
2016-08-09ND
2016-08-092.80 ppb
2016-08-094.20 ppb
2016-08-094.60 ppb
2016-11-140.500 ppb
2016-11-14ND
2016-11-14ND
2016-11-1426.5 ppb
2016-11-143.40 ppb
2016-11-142.60 ppb
2016-11-14ND
2016-11-143.50 ppb
2017-02-061.70 ppb
2017-02-0615.8 ppb
2017-02-06ND
2017-02-06ND
2017-02-060.300 ppb
2017-02-06ND
2017-02-060.400 ppb
2017-02-06ND
2017-05-252.70 ppb
2017-05-252.30 ppb
2017-05-25ND
2017-05-251.90 ppb
2017-05-254.90 ppb
2017-05-25ND
2017-05-250.300 ppb
2017-05-2521.2 ppb
2017-08-0126.1 ppb
2017-08-016.10 ppb
2017-08-010.800 ppb
2017-08-013.10 ppb
2017-08-01ND
2017-08-01ND
2017-08-01ND
2017-08-012.90 ppb
2017-11-13ND
2017-11-13ND
2017-11-133.10 ppb
2017-11-13ND
2017-11-131.70 ppb
2017-11-1313.4 ppb
2017-11-133.70 ppb
2017-11-132.90 ppb
2017-12-28ND