Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

City of Krum

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.

 

48

Samples

0

Samples exceeding legal limit (MCL)

12

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20182.39 ppb85ND - 8.52 ppb
20190.535 ppb82ND - 2.76 ppb
2020ND80ND
20210.603 ppb82ND - 2.51 ppb
20220.585 ppb82ND - 2.47 ppb
20231.05 ppb81ND - 8.40 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

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
2018-01-10Q18013310162.54 ppb
2018-01-10Q18013310153.99 ppb
2018-04-10Q18146070022.81 ppb
2018-04-10Q18146070011.25 ppb
2018-07-18Q18288600028.52 ppb
2018-07-18Q1828860003ND
2018-10-09Q1840450001ND
2018-10-09Q1840450002ND
2019-01-09Q19015970192.76 ppb
2019-01-09Q19015970201.52 ppb
2019-04-04Q1913696001ND
2019-04-04Q1913696002ND
2019-08-20Q1957155008ND
2019-08-20Q1957155007ND
2019-10-15Q1972688001ND
2019-10-15Q1972688002ND
2020-02-03Q2004501001ND
2020-02-03Q2004501002ND
2020-05-11Q2018215011ND
2020-05-11Q2018215012ND
2020-08-04Q2030359001ND
2020-08-04Q2030359002ND
2020-10-06Q2039052022ND
2020-10-06Q2039052023ND
2021-01-20Q2101424005ND
2021-01-20Q2101424006ND
2021-05-25Q2113519001ND
2021-05-25Q2113519002ND
2021-08-19Q21225420012.51 ppb
2021-08-19Q21225420022.31 ppb
2021-11-18Q2132474012ND
2021-11-18Q2132474013ND
2022-02-08Q2204313011ND
2022-02-08Q2204313012ND
2022-04-13Q2211388001ND
2022-04-13Q2211388002ND
2022-08-02Q22220110012.47 ppb
2022-08-02Q2222011002ND
2022-10-19Q2231852015ND
2022-10-19Q22318520162.21 ppb
2023-03-15Q23102400018.40 ppb
2023-03-15Q2310240002ND
2023-06-12Q2322093001ND
2023-06-12Q2322093002ND
2023-08-14Q2333742005ND
2023-08-14Q2333742006ND
2023-11-07Q2347808010ND
2023-11-07Q2347808011ND