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EWG's Tap Water Database — 2021 UPDATE

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Total trihalomethanes (TTHMs)

Waipahu-Ewa-Waianae

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.

MORE ABOUT THIS CONTAMINANT

 

175

Samples

0

Samples exceeding legal limit (MCL)

106

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20142.08 ppb4019ND - 36.0 ppb
20150.687 ppb2516ND - 2.70 ppb
20160.991 ppb2114ND - 3.00 ppb
20171.13 ppb4926ND - 22.0 ppb
20181.27 ppb2016ND - 2.50 ppb
20191.09 ppb2015ND - 2.80 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
2014-01-132014011506631.90 ppb
2014-01-15201401170377ND
2014-01-15201401170388ND
2014-01-182014012202250.560 ppb
2014-01-18201401220226ND
2014-01-182014012202271.60 ppb
2014-01-182014012202283.80 ppb
2014-01-21201401230463ND
2014-01-21201401230462ND
2014-01-21201401230464ND
2014-01-21201401230465ND
2014-01-2420140128045326.0 ppb
2014-01-24201401280404ND
2014-01-242014012804050.720 ppb
2014-01-25201401280407ND
2014-01-26201401280406ND
2014-01-26201401280432ND
2014-01-29201401310166ND
2014-01-302014020100050.570 ppb
2014-02-18201402200355ND
2014-03-05201403070205ND
2014-03-10201403120663ND
2014-03-102014031206601.10 ppb
2014-03-112014031305960.660 ppb
2014-03-1320140319054136.0 ppb
2014-04-01201404030471ND
2014-04-04201404080622ND
2014-06-022014060408090.570 ppb
2014-06-022014060408081.80 ppb
2014-06-032014060700970.800 ppb
2014-07-08201407100610ND
2014-07-23201407250222ND
2014-07-23201407250456ND
2014-09-092014091208050.690 ppb
2014-09-102014091208021.30 ppb
2014-09-102014091208030.790 ppb
2014-10-062014100902002.20 ppb
2014-12-01201412040365ND
2014-12-022014120403630.940 ppb
2014-12-022014120403621.000 ppb
2015-01-062015010803901.80 ppb
2015-01-062015010803910.710 ppb
2015-01-06201501080399ND
2015-01-15201501160297ND
2015-01-152015011602980.780 ppb
2015-01-222015012304040.940 ppb
2015-01-26201501270096ND
2015-03-31201504020267ND
2015-04-012015040302411.70 ppb
2015-04-012015040302420.900 ppb
2015-04-01201504030243ND
2015-04-132015041505860.930 ppb
2015-05-11201505130557ND
2015-07-072015070801640.530 ppb
2015-07-132015071505641.50 ppb
2015-07-132015071505650.560 ppb
2015-07-202015072204262.70 ppb
2015-08-31201509020193ND
2015-08-31201509020194ND
2015-09-292015100102240.540 ppb
2015-10-052015100701950.590 ppb
2015-10-062015091601141.20 ppb
2015-10-062015091601150.820 ppb
2015-10-202015102303010.970 ppb
2015-12-28201512180364ND
2016-01-092.50 ppb
2016-01-120.510 ppb
2016-01-12ND
2016-01-141.50 ppb
2016-01-21ND
2016-01-251.80 ppb
2016-01-26ND
2016-04-060.860 ppb
2016-04-061.20 ppb
2016-04-121.40 ppb
2016-04-19ND
2016-07-050.970 ppb
2016-07-052.00 ppb
2016-07-062.20 ppb
2016-07-061.20 ppb
2016-10-060.680 ppb
2016-10-061.000 ppb
2016-10-06ND
2016-10-123.00 ppb
2016-11-14ND
2016-12-14ND
2017-01-061.40 ppb
2017-01-09ND
2017-01-10ND
2017-01-100.580 ppb
2017-01-100.970 ppb
2017-01-10ND
2017-01-11ND
2017-01-170.670 ppb
2017-01-241.40 ppb
2017-01-241.60 ppb
2017-01-25ND
2017-01-26ND
2017-02-02ND
2017-02-130.550 ppb
2017-02-132.20 ppb
2017-02-16ND
2017-02-221.50 ppb
2017-02-22ND
2017-02-23ND
2017-02-27ND
2017-03-13ND
2017-04-03ND
2017-04-050.560 ppb
2017-04-101.30 ppb
2017-04-1722.0 ppb
2017-04-251.60 ppb
2017-06-261.40 ppb
2017-07-030.780 ppb
2017-07-032.40 ppb
2017-07-031.30 ppb
2017-07-201.000 ppb
2017-10-030.840 ppb
2017-10-032.30 ppb
2017-10-050.770 ppb
2017-10-09ND
2017-10-11ND
2017-10-13ND
2017-10-162.20 ppb
2017-10-16ND
2017-10-161.80 ppb
2017-10-17ND
2017-10-18ND
2017-10-180.650 ppb
2017-10-231.10 ppb
2017-10-24ND
2017-10-24ND
2017-10-24ND
2017-10-25ND
2017-10-252.60 ppb
2018-01-102018010300871.000 ppb
2018-01-102018010300821.50 ppb
2018-01-122018010300812.00 ppb
2018-01-182018011906201.60 ppb
2018-01-22201801230704ND
2018-01-24201712280233ND
2018-01-25201712280229ND
2018-04-022018040409730.900 ppb
2018-04-022018040409712.50 ppb
2018-04-022018040409701.90 ppb
2018-04-162018041709231.70 ppb
2018-07-062018071110631.10 ppb
2018-07-062018071110621.40 ppb
2018-07-092018071113592.00 ppb
2018-08-132018081402731.60 ppb
2018-08-21201808130257ND
2018-10-032018100505612.30 ppb
2018-10-052018100906400.870 ppb
2018-10-052018100906392.20 ppb
2018-10-172018101804940.910 ppb
2019-01-112019011501541.000 ppb
2019-01-112019011501531.10 ppb
2019-01-172019011801190.750 ppb
2019-01-24201901250061ND
2019-01-242019012500570.990 ppb
2019-01-28201901290128ND
2019-01-28201901290129ND
2019-04-022019040401551.000 ppb
2019-04-022019040401542.20 ppb
2019-04-032019040502041.10 ppb
2019-04-042019040502372.10 ppb
2019-07-082019071004680.880 ppb
2019-07-082019071004670.810 ppb
2019-07-092019071104002.60 ppb
2019-07-092019071004501.000 ppb
2019-07-30201908010178ND
2019-10-04201910080585ND
2019-10-072019100905581.10 ppb
2019-10-072019100905572.80 ppb
2019-10-102019091706402.40 ppb