Trichloroacetic acid
National Park Water Department
Trichloroacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 1.21 ppb | 8 | 7 | ND - 1.83 ppb |
| 2015 | 0.874 ppb | 8 | 6 | ND - 1.57 ppb |
| 2016 | 0.945 ppb | 8 | 6 | ND - 1.83 ppb |
| 2017 | 0.875 ppb | 8 | 5 | ND - 1.90 ppb |
| 2018 | 1.33 ppb | 12 | 10 | ND - 2.30 ppb |
| 2019 | 1.84 ppb | 8 | 8 | 1.50 ppb - 3.20 ppb |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 0.1 ppb
The EWG Health Guideline of 0.1 ppb for trichloroacetic acid was proposed in 2020 by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk.a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2014-01-24 | L4906385-2 | 1.83 ppb |
| 2014-01-24 | L4906385-1 | ND |
| 2014-04-15 | L4982742-1 | 1.16 ppb |
| 2014-04-15 | L4982742-2 | 1.38 ppb |
| 2014-07-14 | L5122666-2 | 1.81 ppb |
| 2014-07-14 | L5122666-1 | 1.65 ppb |
| 2014-11-17 | L5255666-2 | 1.26 ppb |
| 2014-11-17 | L5255666-1 | 0.610 ppb |
| 2015-01-15 | L5372127-1 | 1.57 ppb |
| 2015-01-15 | L5372127-2 | 1.38 ppb |
| 2015-04-21 | L5506269-2 | 1.37 ppb |
| 2015-04-21 | L5506269-1 | ND |
| 2015-07-14 | L5666240-2 | 0.770 ppb |
| 2015-07-14 | L5666240-1 | ND |
| 2015-10-12 | L5827794-2 | 1.52 ppb |
| 2015-10-12 | L5827794-1 | 0.380 ppb |
| 2016-01-11 | L5974043-2 | 1.83 ppb |
| 2016-01-11 | L5974043-1 | 1.23 ppb |
| 2016-04-14 | 3431764 | 1.000 ppb |
| 2016-04-14 | 3431763 | 1.000 ppb |
| 2016-07-15 | 3494583 | 1.40 ppb |
| 2016-07-15 | 3494582 | 1.10 ppb |
| 2016-10-10 | 3562245 | ND |
| 2016-10-10 | 3562244 | ND |
| 2017-01-10 | 3618771 | 1.50 ppb |
| 2017-01-10 | 3618772 | 1.30 ppb |
| 2017-04-11 | 3675217 | 1.90 ppb |
| 2017-04-11 | 3675218 | 1.20 ppb |
| 2017-07-12 | 3733121 | 1.10 ppb |
| 2017-07-12 | 3733122 | ND |
| 2017-10-13 | 3801338 | ND |
| 2017-10-13 | 3801339 | ND |
| 2018-01-09 | 2287980001 | ND |
| 2018-01-09 | 2287980002 | 1.80 ppb |
| 2018-01-11 | 3851889 | 1.000 ppb |
| 2018-01-11 | 3851890 | 1.30 ppb |
| 2018-04-09 | 2308057001 | 2.10 ppb |
| 2018-04-09 | 2308057002 | 2.00 ppb |
| 2018-04-13 | 3914855 | 1.50 ppb |
| 2018-04-13 | 3914854 | 1.60 ppb |
| 2018-07-09 | 2325720001 | 1.000 ppb |
| 2018-07-09 | 2325720002 | 1.30 ppb |
| 2018-10-08 | 2343183001 | 2.30 ppb |
| 2018-10-08 | 2343183002 | ND |
| 2019-01-08 | 3010048001 | 1.60 ppb |
| 2019-01-08 | 3010046001 | 3.20 ppb |
| 2019-04-05 | 3026945002 | 1.60 ppb |
| 2019-04-05 | 3026945001 | 1.60 ppb |
| 2019-07-08 | 3044131001 | 1.80 ppb |
| 2019-07-08 | 3044131002 | 1.70 ppb |
| 2019-10-08 | 3062636001 | 1.50 ppb |
| 2019-10-08 | 3062636002 | 1.70 ppb |