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EWG's Tap Water Database — 2021 UPDATE

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Total trihalomethanes (TTHMs)

City of Riverton

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

 

120

Samples

0

Samples exceeding legal limit (MCL)

71

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20144.98 ppb308ND - 40.3 ppb
20158.75 ppb2015ND - 38.0 ppb
201613.5 ppb2114ND - 45.0 ppb
20177.39 ppb3117ND - 38.0 ppb
201812.1 ppb1817ND - 38.0 ppb
2019N/A00N/A

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
2014-01-08C14010208-004ND
2014-01-08C14010208-001ND
2014-01-08C14010208-0026.98 ppb
2014-01-08C14010208-003ND
2014-04-08C14040294-001AND
2014-04-08C14040294-002AND
2014-04-08C14040294-003AND
2014-04-08C14040294-004AND
2014-07-10C14070443-001A40.3 ppb
2014-07-10C14070443-002A29.8 ppb
2014-07-10C14070443-003A21.7 ppb
2014-07-10C14070443-004AND
2014-07-14C14070510-005L9.60 ppb
2014-07-14C14070510-006LND
2014-07-14C14070510-007LND
2014-07-14C14070510-008LND
2014-07-14C14070510-009LND
2014-07-14C14070510-010LND
2014-07-14C14070510-011LND
2014-07-14C14070510-012LND
2014-07-14C14070510-013LND
2014-07-14C14070510-014LND
2014-07-14C14070510-001LND
2014-07-14C14070510-002LND
2014-07-14C14070510-003LND
2014-07-14C14070510-004LND
2014-10-07C14100443-003A12.0 ppb
2014-10-07C14100443-004A27.0 ppb
2014-10-07C14100443-001AND
2014-10-07C14100443-002A2.00 ppb
2015-01-06C15010106-001A4.10 ppb
2015-01-06C15010106-002AND
2015-01-06C15010106-003A1.40 ppb
2015-01-06C15010106-004A6.20 ppb
2015-04-08C15040303-001A2.50 ppb
2015-04-08C15040303-002AND
2015-04-08C15040303-003A0.910 ppb
2015-04-08C15040303-004A5.40 ppb
2015-04-14C15040475-001KND
2015-06-25C15061008-013L2.10 ppb
2015-07-06C15070185-001A19.0 ppb
2015-07-06C15070185-002A21.0 ppb
2015-07-06C15070185-003A38.0 ppb
2015-07-06C15070185-004A38.0 ppb
2015-08-11C15080418-001JND
2015-10-06C15100259-001A2.80 ppb
2015-10-06C15100259-002A0.520 ppb
2015-10-06C15100259-003A11.0 ppb
2015-10-06C15100259-004A22.0 ppb
2015-10-26C15100814-001HND
2016-03-07C16030282-001HND
2016-04-11C16040331-001A4.10 ppb
2016-04-11C16040331-002AND
2016-04-11C16040331-003A0.540 ppb
2016-04-11C16040331-004AND
2016-06-13C16060466-007END
2016-06-13C16060466-016HND
2016-07-12C16070385-001A12.0 ppb
2016-07-12C16070385-002A21.0 ppb
2016-07-12C16070385-003A44.0 ppb
2016-07-12C16070385-004A34.0 ppb
2016-08-18C16080799-001A43.0 ppb
2016-08-18C16080799-002A25.0 ppb
2016-08-18C16080799-003A45.0 ppb
2016-08-18C16080799-004A34.0 ppb
2016-09-07C16090266-001AND
2016-10-10C16100314-001B9.40 ppb
2016-10-10C16100314-002B0.820 ppb
2016-10-10C16100314-003B2.20 ppb
2016-10-10C16100314-004B8.60 ppb
2016-12-12C16120340-001HND
2017-01-09C17010195-001A5.10 ppb
2017-01-09C17010195-002AND
2017-01-09C17010195-003A1.10 ppb
2017-01-09C17010195-004AND
2017-04-10C17040300-001A2.00 ppb
2017-04-10C17040300-002A0.740 ppb
2017-04-10C17040300-003A1.10 ppb
2017-04-10C17040300-004AND
2017-06-06C17060229-001END
2017-06-06C17060229-002END
2017-06-06C17060229-003E0.760 ppb
2017-06-06C17060229-004END
2017-06-06C17060229-005END
2017-06-06C17060229-006E2.20 ppb
2017-06-06C17060229-007E1.10 ppb
2017-06-06C17060229-008END
2017-06-06C17060229-009END
2017-06-06C17060229-010END
2017-06-06C17060229-011END
2017-06-06C17060229-012END
2017-06-06C17060229-013E30.8 ppb
2017-06-06C17060229-014END
2017-07-11C17070375-001A38.0 ppb
2017-07-11C17070375-002A19.0 ppb
2017-07-11C17070375-003A33.0 ppb
2017-07-11C17070375-004A28.0 ppb
2017-07-17C17070545-001END
2017-10-10C17100399-001A14.0 ppb
2017-10-10C17100399-002A1.10 ppb
2017-10-10C17100399-003A32.0 ppb
2017-10-10C17100399-004A19.0 ppb
2018-01-08C18010253-004A7.00 ppb
2018-01-08C18010253-003A6.60 ppb
2018-01-08C18010253-002A1.70 ppb
2018-01-08C18010253-001A5.40 ppb
2018-04-09C18040336-004A4.70 ppb
2018-04-09C18040336-003A5.90 ppb
2018-04-09C18040336-002A1.20 ppb
2018-04-09C18040336-001A2.60 ppb
2018-06-04C18060169-052D2.10 ppb
2018-07-11C18070431-002A20.0 ppb
2018-07-11C18070431-001A38.0 ppb
2018-07-11C18070431-004A35.0 ppb
2018-07-11C18070431-003A34.0 ppb
2018-10-09C18100418-003A11.0 ppb
2018-10-09C18100418-002A1.10 ppb
2018-10-09C18100418-001A19.0 ppb
2018-10-09C18100418-004A22.0 ppb
2018-10-15C18100603-001AND