Know Your Environment. Protect Your Health.

Total trihalomethanes (TTHMs)

Lynwood Park Mutual Water Company

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)

7

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.625 ppb81ND - 5.00 ppb
20193.26 ppb84ND - 17.1 ppb
20200.325 ppb81ND - 2.60 ppb
2021ND80ND
20220.513 ppb81ND - 4.10 ppb
2023ND80ND

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
2018-03-07CA1910081_DST_801-201803071037ND
2018-03-07CA1910081_DST_800-2018030710575.00 ppb
2018-06-06CA1910081_DST_800-201806061148ND
2018-06-06CA1910081_DST_801-201806061131ND
2018-09-12CA1910081_DST_800-201809121156ND
2018-09-12CA1910081_DST_801-201809121137ND
2018-12-12CA1910081_DST_800-201812121200ND
2018-12-12CA1910081_DST_801-201812121144ND
2019-03-13CA1910081_DST_801-201903131057ND
2019-03-13CA1910081_DST_800-201903131113ND
2019-06-24CA1910081_DST_800-201906240826ND
2019-06-24CA1910081_DST_801-2019062408574.00 ppb
2019-09-09CA1910081_DST_800-20190909092217.1 ppb
2019-09-09CA1910081_DST_801-2019090909483.90 ppb
2019-12-17CA1910081_DST_800-2019121708581.10 ppb
2019-12-17CA1910081_DST_801-201912170927ND
2020-03-02CA1910081_DST_801-2020030212102.60 ppb
2020-03-02CA1910081_DST_800-202003021120ND
2020-06-01CA1910081_DST_801-202006011205ND
2020-06-01CA1910081_DST_800-202006011125ND
2020-09-08CA1910081_DST_800-202009081120ND
2020-09-08CA1910081_DST_801-202009081135ND
2020-12-07CA1910081_DST_801-202012071140ND
2020-12-07CA1910081_DST_800-202012071110ND
2021-03-08CA1910081_DST_801-202103081130ND
2021-03-08CA1910081_DST_800-202103081100ND
2021-06-01CA1910081_DST_800-202106011115ND
2021-06-01CA1910081_DST_801-202106011145ND
2021-09-13CA1910081_DST_800-202109131130ND
2021-09-13CA1910081_DST_801-202109131201ND
2021-12-20CA1910081_DST_800-202112201115ND
2021-12-20CA1910081_DST_801-202112201145ND
2022-03-07CA1910081_DST_800-202203071130ND
2022-03-07CA1910081_DST_801-202203071200ND
2022-06-13CA1910081_DST_801-202206131135ND
2022-06-13CA1910081_DST_800-2022061311104.10 ppb
2022-09-28CA1910081_DST_800-202209281115ND
2022-09-28CA1910081_DST_801-202209281130ND
2022-12-05CA1910081_DST_800-202212051100ND
2022-12-05CA1910081_DST_801-202212051130ND
2023-03-13CA1910081_DST_800-202303131215ND
2023-03-13CA1910081_DST_801-202303131245ND
2023-06-12CA1910081_DST_800-202306121130ND
2023-06-12CA1910081_DST_801-202306121200ND
2023-09-11CA1910081_DST_800-202309111100ND
2023-09-11CA1910081_DST_801-202309111130ND
2023-12-11CA1910081_DST_800-202312111130ND
2023-12-11CA1910081_DST_801-202312111200ND