Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

Aqua Pa Hatboro

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.

 

100

Samples

0

Samples exceeding legal limit (MCL)

78

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20188.51 ppb2015ND - 53.2 ppb
20197.49 ppb1614ND - 39.0 ppb
20208.17 ppb1612ND - 55.1 ppb
20217.28 ppb1610ND - 29.9 ppb
20227.79 ppb1613ND - 41.6 ppb
202321.5 ppb1614ND - 56.9 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
2018-01-03AF72704ND
2018-01-03AF727031.90 ppb
2018-01-03AF727025.20 ppb
2018-01-03AF727015.10 ppb
2018-04-04AF804020.700 ppb
2018-04-04AF80403ND
2018-04-04AF8040122.1 ppb
2018-04-25AF8224132.1 ppb
2018-07-03AF886021.80 ppb
2018-07-03AF886000.600 ppb
2018-07-03AF88601ND
2018-07-03AF8859953.2 ppb
2018-07-31AF9116526.3 ppb
2018-07-31AF91167ND
2018-07-31AF911647.60 ppb
2018-07-31AF911660.900 ppb
2018-10-03AF971891.10 ppb
2018-10-03AF97188ND
2018-10-03AF971870.600 ppb
2018-10-03AF9718611.0 ppb
2019-01-02AG050871.30 ppb
2019-01-02AG050860.500 ppb
2019-01-02AG050850.700 ppb
2019-01-02AG0508418.2 ppb
2019-04-03AG13097ND
2019-04-03AG130982.80 ppb
2019-04-03AG1309511.0 ppb
2019-04-03AG130961.20 ppb
2019-07-03AG2251539.0 ppb
2019-07-03AG22507ND
2019-07-03AG225060.600 ppb
2019-07-03AG225080.700 ppb
2019-10-02AG343670.500 ppb
2019-10-02AG3436623.2 ppb
2019-10-02AG343683.30 ppb
2019-10-02AG3436516.8 ppb
2020-01-030.500 ppb
2020-01-031.30 ppb
2020-01-033.20 ppb
2020-01-036.10 ppb
2020-04-01ND
2020-04-010.500 ppb
2020-04-01ND
2020-04-0119.3 ppb
2020-07-01ND
2020-07-010.600 ppb
2020-07-013.20 ppb
2020-07-0155.1 ppb
2020-10-0732.2 ppb
2020-10-078.20 ppb
2020-10-070.500 ppb
2020-10-07ND
2021-01-061.50 ppb
2021-01-0613.9 ppb
2021-01-060.700 ppb
2021-01-06ND
2021-04-0721.9 ppb
2021-04-0721.4 ppb
2021-04-07ND
2021-04-07ND
2021-07-02ND
2021-07-020.530 ppb
2021-07-02ND
2021-07-0229.9 ppb
2021-10-060.520 ppb
2021-10-060.670 ppb
2021-10-06ND
2021-10-0625.4 ppb
2022-01-0520.8 ppb
2022-01-051.10 ppb
2022-01-051.60 ppb
2022-01-050.800 ppb
2022-04-062.00 ppb
2022-04-0621.5 ppb
2022-04-061.30 ppb
2022-04-061.000 ppb
2022-07-0641.6 ppb
2022-07-061.70 ppb
2022-07-061.70 ppb
2022-07-06ND
2022-10-05ND
2022-10-0529.0 ppb
2022-10-05ND
2022-10-050.600 ppb
2023-01-1121.4 ppb
2023-01-1119.9 ppb
2023-01-112.80 ppb
2023-01-119.50 ppb
2023-04-12ND
2023-04-1229.4 ppb
2023-04-129.30 ppb
2023-04-120.700 ppb
2023-07-1256.9 ppb
2023-07-120.500 ppb
2023-07-1226.6 ppb
2023-07-1256.4 ppb
2023-10-11ND
2023-10-1133.0 ppb
2023-10-1137.4 ppb
2023-10-1140.1 ppb