Chloroform
City of Gonzales Water System
Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Read More.
In addition to tap water disinfection, chloroform pollution in the environment also comes from industrial discharges from pulp and paper mills, and from urban wastewater effluent. Human studies show that chloroform damages the kidneys, liver and central nervous system. In animals, chloroform causes infertility, birth defects and cancer.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 3.73 ppb | 32 | 16 | ND - 55.7 ppb |
| 2019 | 1.41 ppb | 32 | 22 | ND - 15.1 ppb |
| 2020 | 0.733 ppb | 16 | 16 | 0.550 ppb - 1.20 ppb |
| 2021 | 0.609 ppb | 16 | 15 | ND - 0.850 ppb |
| 2022 | 2.85 ppb | 16 | 11 | ND - 17.0 ppb |
| 2023 | 0.543 ppb | 16 | 12 | ND - 1.20 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.4 ppb
The EWG Health Guideline of 0.4 ppb for chloroform was based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer and harm to fetal growth and development.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-02-02 | 35371907001 | 0.390 ppb |
| 2018-02-02 | 35371907002 | 0.520 ppb |
| 2018-02-02 | 35371907003 | 0.540 ppb |
| 2018-02-02 | 35371907004 | 0.500 ppb |
| 2018-02-02 | 35371907001 | 0.390 ppb |
| 2018-02-02 | 35371907002 | 0.520 ppb |
| 2018-02-02 | 35371907003 | 0.540 ppb |
| 2018-02-02 | 35371907004 | 0.500 ppb |
| 2018-05-18 | 35393231001 | ND |
| 2018-05-18 | 35393231002 | ND |
| 2018-05-18 | 35393231003 | ND |
| 2018-05-18 | 35393231004 | 55.7 ppb |
| 2018-05-18 | 35393231001 | ND |
| 2018-05-18 | 35393231002 | ND |
| 2018-05-18 | 35393231003 | ND |
| 2018-05-18 | 35393231004 | 55.7 ppb |
| 2018-08-03 | 35408663001 | ND |
| 2018-08-03 | 35408663002 | 0.630 ppb |
| 2018-08-03 | 35408663003 | 0.720 ppb |
| 2018-08-03 | 35408663004 | 0.700 ppb |
| 2018-08-03 | 35408663001 | ND |
| 2018-08-03 | 35408663002 | 0.630 ppb |
| 2018-08-03 | 35408663003 | 0.720 ppb |
| 2018-08-03 | 35408663004 | 0.700 ppb |
| 2018-11-01 | 35428204001 | ND |
| 2018-11-01 | 35428204002 | ND |
| 2018-11-01 | 35428204003 | ND |
| 2018-11-01 | 35428204004 | ND |
| 2018-11-01 | 35428204001 | ND |
| 2018-11-01 | 35428204002 | ND |
| 2018-11-01 | 35428204003 | ND |
| 2018-11-01 | 35428204004 | ND |
| 2019-02-07 | 35447124001 | 0.550 ppb |
| 2019-02-07 | 35447124002 | 0.510 ppb |
| 2019-02-07 | 35447124003 | 0.690 ppb |
| 2019-02-07 | 35447124004 | 0.700 ppb |
| 2019-02-07 | 35447124001 | 0.550 ppb |
| 2019-02-07 | 35447124002 | 0.510 ppb |
| 2019-02-07 | 35447124003 | 0.690 ppb |
| 2019-02-07 | 35447124004 | 0.700 ppb |
| 2019-05-08 | 35468287001 | 0.360 ppb |
| 2019-05-08 | 35468287002 | 0.690 ppb |
| 2019-05-08 | 35468287003 | 15.1 ppb |
| 2019-05-08 | 35468287004 | ND |
| 2019-05-08 | 35468287001 | 0.360 ppb |
| 2019-05-08 | 35468287002 | 0.690 ppb |
| 2019-05-08 | 35468287003 | 15.1 ppb |
| 2019-05-08 | 35468287004 | ND |
| 2019-08-06 | 35488733001 | 1.30 ppb |
| 2019-08-06 | 35488733002 | 0.930 ppb |
| 2019-08-06 | 35488733003 | 1.10 ppb |
| 2019-08-06 | 35488733004 | 0.550 ppb |
| 2019-08-06 | 35488733001 | 1.30 ppb |
| 2019-08-06 | 35488733002 | 0.930 ppb |
| 2019-08-06 | 35488733003 | 1.10 ppb |
| 2019-08-06 | 35488733004 | 0.550 ppb |
| 2019-11-06 | 35511100001 | ND |
| 2019-11-06 | 35511100002 | ND |
| 2019-11-06 | 35511100003 | ND |
| 2019-11-06 | 35511100004 | ND |
| 2019-11-06 | 35511100001 | ND |
| 2019-11-06 | 35511100002 | ND |
| 2019-11-06 | 35511100003 | ND |
| 2019-11-06 | 35511100004 | ND |
| 2020-02-04 | 35529352001 | 0.660 ppb |
| 2020-02-04 | 35529352002 | 0.700 ppb |
| 2020-02-04 | 35529352003 | 0.590 ppb |
| 2020-02-04 | 35529352004 | 0.650 ppb |
| 2020-05-12 | 35550484001 | 0.740 ppb |
| 2020-05-12 | 35550484002 | 1.000 ppb |
| 2020-05-12 | 35550484003 | 1.20 ppb |
| 2020-05-12 | 35550484004 | 0.940 ppb |
| 2020-08-04 | 35569238001 | 0.630 ppb |
| 2020-08-04 | 35569238002 | 0.660 ppb |
| 2020-08-04 | 35569238003 | 0.550 ppb |
| 2020-08-04 | 35569238004 | 0.660 ppb |
| 2020-11-04 | 35590522001 | 0.600 ppb |
| 2020-11-04 | 35590522002 | 0.740 ppb |
| 2020-11-04 | 35590522003 | 0.690 ppb |
| 2020-11-04 | 35590522004 | 0.710 ppb |
| 2021-02-01 | 35610064001 | 0.550 ppb |
| 2021-02-01 | 35610064002 | 0.670 ppb |
| 2021-02-01 | 35610064003 | 0.580 ppb |
| 2021-02-01 | 35610064004 | 0.610 ppb |
| 2021-05-03 | 35631688001 | 0.790 ppb |
| 2021-05-03 | 35631688002 | 0.730 ppb |
| 2021-05-03 | 35631688003 | 0.850 ppb |
| 2021-05-03 | 35631688004 | 0.780 ppb |
| 2021-08-05 | 35653948001 | 0.500 ppb |
| 2021-08-05 | 35653948002 | 0.390 ppb |
| 2021-08-05 | 35653948003 | 0.500 ppb |
| 2021-08-05 | 35653948004 | 0.670 ppb |
| 2021-11-03 | 35676417001 | 0.760 ppb |
| 2021-11-03 | 35676417002 | 0.670 ppb |
| 2021-11-03 | 35676417003 | 0.700 ppb |
| 2021-11-03 | 35676417004 | ND |
| 2022-02-17 | 35698373001 | 0.650 ppb |
| 2022-02-17 | 35698373002 | 0.700 ppb |
| 2022-02-17 | 35698373003 | ND |
| 2022-02-17 | 35698373004 | ND |
| 2022-05-09 | 35717413001 | 0.900 ppb |
| 2022-05-09 | 35717413002 | ND |
| 2022-05-09 | 35717413003 | ND |
| 2022-05-09 | 35717413004 | ND |
| 2022-08-10 | 35739070001 | 17.0 ppb |
| 2022-08-10 | 35739070002 | 3.70 ppb |
| 2022-08-10 | 35739070003 | 10.4 ppb |
| 2022-08-10 | 35739070004 | 9.80 ppb |
| 2022-11-03 | 35757716001 | 0.790 ppb |
| 2022-11-03 | 35757716002 | 0.500 ppb |
| 2022-11-03 | 35757716003 | 0.590 ppb |
| 2022-11-03 | 35757716004 | 0.580 ppb |
| 2023-02-02 | 35776737001 | 0.450 ppb |
| 2023-02-02 | 35776737002 | 0.720 ppb |
| 2023-02-02 | 35776737003 | 0.840 ppb |
| 2023-02-02 | 35776737004 | 0.680 ppb |
| 2023-05-04 | 35797439001 | ND |
| 2023-05-04 | 35797439002 | 0.550 ppb |
| 2023-05-04 | 35797439003 | 0.650 ppb |
| 2023-05-04 | 35797439004 | 0.490 ppb |
| 2023-08-02 | 35817723001 | ND |
| 2023-08-02 | 35817723002 | 0.940 ppb |
| 2023-08-02 | 35817723003 | 1.20 ppb |
| 2023-08-02 | 35817723004 | 0.650 ppb |
| 2023-11-07 | 35840526001 | ND |
| 2023-11-07 | 35840526002 | 0.750 ppb |
| 2023-11-07 | 35840526003 | 0.760 ppb |
| 2023-11-07 | 35840526004 | ND |