Total trihalomethanes (TTHMs)

Two Rivers Utilities

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

192

Samples

Samples exceeding legal limit (MCL)

192

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2013	N/A	0	0	N/A
2014	49.5 ppb	32	32	17.8 ppb - 106.0 ppb
2015	53.7 ppb	32	32	28.0 ppb - 81.1 ppb
2016	44.3 ppb	32	32	23.7 ppb - 79.1 ppb
2017	44.5 ppb	32	32	17.8 ppb - 80.7 ppb
2018	45.9 ppb	32	32	15.7 ppb - 104.2 ppb
2019	37.6 ppb	32	32	19.7 ppb - 80.0 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.15 ppb

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
2014-01-27	2963636	23.5 ppb
2014-01-27	2963637	33.8 ppb
2014-01-27	2963638	29.2 ppb
2014-01-27	2963639	27.7 ppb
2014-01-27	2963640	17.8 ppb
2014-01-27	2963641	27.7 ppb
2014-01-27	2963642	39.1 ppb
2014-01-27	2963643	30.8 ppb
2014-04-23	3013723	38.6 ppb
2014-04-23	3013724	49.9 ppb
2014-04-23	3013725	42.2 ppb
2014-04-23	3013726	40.9 ppb
2014-04-23	3013727	30.0 ppb
2014-04-23	3013728	40.0 ppb
2014-04-23	3013729	54.7 ppb
2014-04-23	3013730	45.3 ppb
2014-07-22	3067645	63.1 ppb
2014-07-22	3067646	80.7 ppb
2014-07-22	3067647	75.6 ppb
2014-07-22	3067648	65.5 ppb
2014-07-22	3067649	54.1 ppb
2014-07-22	3067650	76.4 ppb
2014-07-22	3067651	106.0 ppb
2014-07-22	3067652	83.7 ppb
2014-10-23	3128106	44.2 ppb
2014-10-23	3128107	62.3 ppb
2014-10-23	3128108	58.2 ppb
2014-10-23	3128109	46.1 ppb
2014-10-23	3128110	36.7 ppb
2014-10-23	3128111	46.7 ppb
2014-10-23	3128112	62.2 ppb
2014-10-23	3128113	52.6 ppb
2015-01-22		37.2 ppb
2015-01-22		46.6 ppb
2015-01-22		39.3 ppb
2015-01-22		36.5 ppb
2015-01-22		28.0 ppb
2015-01-22		33.9 ppb
2015-01-22		51.2 ppb
2015-01-22		40.3 ppb
2015-04-23		54.6 ppb
2015-04-23		66.9 ppb
2015-04-23		49.5 ppb
2015-04-23		54.4 ppb
2015-04-23		43.9 ppb
2015-04-23		54.0 ppb
2015-04-23		65.8 ppb
2015-04-23		54.1 ppb
2015-07-23		60.4 ppb
2015-07-23		67.0 ppb
2015-07-23		62.6 ppb
2015-07-23		59.8 ppb
2015-07-23		47.3 ppb
2015-07-23		62.6 ppb
2015-07-23		81.1 ppb
2015-07-23		61.3 ppb
2015-10-26		60.4 ppb
2015-10-26		75.8 ppb
2015-10-26		54.9 ppb
2015-10-26		48.0 ppb
2015-10-26		38.9 ppb
2015-10-26		45.1 ppb
2015-10-26		75.2 ppb
2015-10-26		61.5 ppb
2016-01-21	3389478	34.3 ppb
2016-01-21	3389479	56.0 ppb
2016-01-21	3389480	40.4 ppb
2016-01-21	3389481	36.1 ppb
2016-01-21	3389482	23.8 ppb
2016-01-21	3389483	34.7 ppb
2016-01-21	3389484	55.0 ppb
2016-01-21	3389485	48.8 ppb
2016-04-21	3435395	36.1 ppb
2016-04-21	3435396	46.9 ppb
2016-04-21	3435397	36.3 ppb
2016-04-21	3435398	31.9 ppb
2016-04-21	3435399	23.7 ppb
2016-04-21	3435400	30.8 ppb
2016-04-21	3435401	43.6 ppb
2016-04-21	3435402	37.5 ppb
2016-07-21	3501170	62.6 ppb
2016-07-21	3501171	79.1 ppb
2016-07-21	3501172	56.8 ppb
2016-07-21	3501173	37.1 ppb
2016-07-21	3501174	49.4 ppb
2016-07-21	3501175	70.2 ppb
2016-07-21	3501176	75.2 ppb
2016-07-21	3501177	52.4 ppb
2016-10-20	3569355	42.8 ppb
2016-10-20	3569356	46.3 ppb
2016-10-20	3569357	44.0 ppb
2016-10-20	3569358	31.2 ppb
2016-10-20	3569359	30.3 ppb
2016-10-20	3569360	32.3 ppb
2016-10-20	3569361	49.9 ppb
2016-10-20	3569362	43.0 ppb
2017-01-23	3625774	26.5 ppb
2017-01-23	3625775	36.9 ppb
2017-01-23	3625776	28.1 ppb
2017-01-23	3625777	24.1 ppb
2017-01-23	3625778	17.8 ppb
2017-01-23	3625779	22.9 ppb
2017-01-23	3625780	37.3 ppb
2017-01-23	3625781	37.2 ppb
2017-04-20	3679453	38.7 ppb
2017-04-20	3679454	53.7 ppb
2017-04-20	3679455	38.9 ppb
2017-04-20	3679456	33.5 ppb
2017-04-20	3679457	27.0 ppb
2017-04-20	3679458	35.9 ppb
2017-04-20	3679459	51.8 ppb
2017-04-20	3679460	42.2 ppb
2017-07-17	3734386	63.5 ppb
2017-07-17	3734387	58.2 ppb
2017-07-17	3734388	73.4 ppb
2017-07-17	3734389	53.1 ppb
2017-07-17	3734390	50.0 ppb
2017-07-17	3734391	54.2 ppb
2017-07-17	3734392	80.7 ppb
2017-07-17	3734393	63.6 ppb
2017-10-23	3805481	41.4 ppb
2017-10-23	3805482	61.5 ppb
2017-10-23	3805483	40.7 ppb
2017-10-23	3805484	37.0 ppb
2017-10-23	3805485	28.4 ppb
2017-10-23	3805486	49.5 ppb
2017-10-23	3805487	64.2 ppb
2017-10-23	3805488	52.7 ppb
2018-01-24	3858775	25.2 ppb
2018-01-24	3858776	36.7 ppb
2018-01-24	3858777	27.7 ppb
2018-01-24	3858778	23.0 ppb
2018-01-24	3858779	15.7 ppb
2018-01-24	3858780	22.5 ppb
2018-01-24	3858781	36.4 ppb
2018-01-24	3858782	28.4 ppb
2018-04-30	3924236	32.7 ppb
2018-04-30	3924237	55.5 ppb
2018-04-30	3924238	38.1 ppb
2018-04-30	3924239	33.4 ppb
2018-04-30	3924240	29.8 ppb
2018-04-30	3924241	33.2 ppb
2018-04-30	3924242	61.7 ppb
2018-04-30	3924243	42.5 ppb
2018-07-17	3991828	67.9 ppb
2018-07-17	3991829	69.0 ppb
2018-07-17	3991830	79.0 ppb
2018-07-17	3991831	54.8 ppb
2018-07-17	3991832	46.1 ppb
2018-07-17	3991833	48.6 ppb
2018-07-17	3991834	61.7 ppb
2018-07-17	3991835	59.9 ppb
2018-10-08	4082370	51.2 ppb
2018-10-08	4082372	63.4 ppb
2018-10-08	4082374	37.7 ppb
2018-10-08	4082376	36.6 ppb
2018-10-08	4082378	38.8 ppb
2018-10-08	4082380	57.3 ppb
2018-10-08	4082382	104.2 ppb
2018-10-08	4082384	51.3 ppb
2019-01-16	4175597	32.5 ppb
2019-01-16	4175598	32.7 ppb
2019-01-16	4175599	21.0 ppb
2019-01-16	4175600	19.7 ppb
2019-01-16	4175601	25.5 ppb
2019-01-16	4175602	24.6 ppb
2019-01-16	4175603	28.1 ppb
2019-01-16	4175604	31.6 ppb
2019-04-03	4248413	31.0 ppb
2019-04-03	4248414	40.0 ppb
2019-04-03	4248415	29.0 ppb
2019-04-03	4248416	21.0 ppb
2019-04-03	4248417	27.0 ppb
2019-04-03	4248418	30.0 ppb
2019-04-03	4248419	35.0 ppb
2019-04-03	4248420	31.0 ppb
2019-07-10	4349055	49.0 ppb
2019-07-10	4349057	51.0 ppb
2019-07-10	4349059	55.0 ppb
2019-07-10	4349061	45.0 ppb
2019-07-10	4349063	34.0 ppb
2019-07-10	4349065	43.0 ppb
2019-07-10	4349067	80.0 ppb
2019-07-10	4349069	50.0 ppb
2019-10-08	4449399	47.0 ppb
2019-10-08	4449401	50.0 ppb
2019-10-08	4449403	50.0 ppb
2019-10-08	4449405	25.0 ppb
2019-10-08	4449407	28.0 ppb
2019-10-08	4449409	30.0 ppb
2019-10-08	4449411	65.0 ppb
2019-10-08	4449413	40.0 ppb