Trichloroacetic acid

City of Napa

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.

MORE ABOUT THIS CONTAMINANT

255

Samples

Samples exceeding legal limit (MCL)

239

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2013	N/A	0	0	N/A
2014	14.7 ppb	40	39	ND - 41.9 ppb
2015	15.0 ppb	44	42	ND - 50.0 ppb
2016	9.50 ppb	38	35	ND - 19.0 ppb
2017	13.0 ppb	42	40	ND - 29.0 ppb
2018	9.65 ppb	44	40	ND - 17.9 ppb
2019	9.97 ppb	47	43	ND - 20.7 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
2014-01-08	3761-007-0935	5.40 ppb
2014-01-08	3761-008-1030	11.2 ppb
2014-01-08	3761-009-1000	11.5 ppb
2014-01-08	3761-010-1050	9.80 ppb
2014-01-08	3761-011-1245	12.4 ppb
2014-01-08	3761-012-1305	12.7 ppb
2014-01-08	3761-024-1230	11.5 ppb
2014-01-08	3761-025-1110	13.3 ppb
2014-01-08	3761-028-1315	11.4 ppb
2014-04-02	3761-006-1245	16.9 ppb
2014-04-02	3761-007-1000	10.3 ppb
2014-04-02	3761-008-1055	ND
2014-04-02	3761-009-1040	25.7 ppb
2014-04-02	3761-010-1110	25.7 ppb
2014-04-02	3761-011-1330	25.9 ppb
2014-04-02	3761-012-1355	31.8 ppb
2014-04-02	3761-024-1315	23.7 ppb
2014-04-02	3761-025-1130	26.8 ppb
2014-04-02	3761-028-1345	1.10 ppb
2014-07-09	3761-005-1145	5.70 ppb
2014-07-09	3761-006-1245	18.9 ppb
2014-07-09	3761-007-0925	4.60 ppb
2014-07-09	3761-008-1030	2.50 ppb
2014-07-09	3761-009-1015	20.0 ppb
2014-07-09	3761-010-1040	9.80 ppb
2014-07-09	3761-011-1410	15.1 ppb
2014-07-09	3761-012-1440	10.9 ppb
2014-07-09	3761-024-1355	41.9 ppb
2014-07-09	3761-025-1105	20.2 ppb
2014-07-09	3761-028-1430	14.3 ppb
2014-10-01	3761-006-1220	18.6 ppb
2014-10-01	3761-007-1010	4.40 ppb
2014-10-01	3761-008-1050	8.80 ppb
2014-10-01	3761-009-1035	11.5 ppb
2014-10-01	3761-010-1105	9.80 ppb
2014-10-01	3761-011-1320	12.9 ppb
2014-10-01	3761-012-1355	10.4 ppb
2014-10-01	3761-024-1300	24.3 ppb
2014-10-01	3761-025-1125	13.0 ppb
2014-10-01	3761-028-1335	24.9 ppb
2015-01-08	9590-007-1000	18.0 ppb
2015-01-08	9590-008-1105	2.60 ppb
2015-01-08	9590-009-1050	46.0 ppb
2015-01-08	9590-010-1115	33.0 ppb
2015-01-08	9590-011-1215	43.0 ppb
2015-01-08	9590-012-1330	31.0 ppb
2015-01-08	9590-024-1155	50.0 ppb
2015-01-08	9590-025-1130	45.0 ppb
2015-01-08	9590-028-1320	31.0 ppb
2015-04-01	9590-007-0950	3.30 ppb
2015-04-01	9590-008-1045	7.90 ppb
2015-04-01	9590-009-1030	7.20 ppb
2015-04-01	9590-010-1055	6.60 ppb
2015-04-01	9590-011-1330	7.30 ppb
2015-04-01	9590-012-1355	6.90 ppb
2015-04-01	9590-024-1315	9.70 ppb
2015-04-01	9590-025-1115	5.70 ppb
2015-04-01	9590-028-1340	ND
2015-07-21	9590-005-1120	5.20 ppb
2015-07-21	9590-006-1415	42.0 ppb
2015-07-21	9590-007-0940	5.20 ppb
2015-07-21	9590-008-1035	14.0 ppb
2015-07-21	9590-009-1020	11.0 ppb
2015-07-21	9590-010-1045	9.30 ppb
2015-07-21	9590-011-1505	11.0 ppb
2015-07-21	9590-012-1530	11.0 ppb
2015-07-21	9590-024-1450	16.0 ppb
2015-07-21	9590-025-1200	15.0 ppb
2015-07-21	9590-028-1520	4.30 ppb
2015-10-07	9590-005-1155	3.60 ppb
2015-10-07	9590-006-1325	41.0 ppb
2015-10-07	9590-007-1110	3.60 ppb
2015-10-07	9590-008-1510	8.80 ppb
2015-10-07	9590-009-1525	7.80 ppb
2015-10-07	9590-010-1455	6.00 ppb
2015-10-07	9590-011-1415	8.40 ppb
2015-10-07	9590-012-1440	7.60 ppb
2015-10-07	9590-024-1400	11.0 ppb
2015-10-07	9590-025-1210	18.0 ppb
2015-10-07	9590-028-1430	5.40 ppb
2015-11-04	9590-006-1220	14.0 ppb
2015-11-04	9590-007-1030	1.20 ppb
2015-12-02	9590-006-1145	25.0 ppb
2015-12-02	9590-007-1030	ND
2016-01-08	9590-007-1210	ND
2016-01-08	9590-008-1245	5.60 ppb
2016-01-08	9590-009-1230	3.50 ppb
2016-01-08	9590-010-1300	2.50 ppb
2016-01-08	9590-011-1355	5.30 ppb
2016-01-08	9590-012-1430	5.30 ppb
2016-01-08	9590-024-1340	5.60 ppb
2016-01-08	9590-025-1320	6.80 ppb
2016-01-08	9590-028-1415	2.70 ppb
2016-04-06	9590-006-1230	7.30 ppb
2016-04-06	9590-008-1100	5.10 ppb
2016-04-06	9590-009-1045	17.0 ppb
2016-04-06	9590-010-1115	18.0 ppb
2016-04-06	9590-011-1345	11.0 ppb
2016-04-06	9590-012-1405	15.0 ppb
2016-04-06	9590-024-1330	12.0 ppb
2016-04-06	9590-025-1130	16.0 ppb
2016-04-06	9590-028-1400	11.0 ppb
2016-05-04	9590-007-1025	12.0 ppb
2016-07-27	9590-007-1245	4.90 ppb
2016-07-27	9590-008-1320	ND
2016-07-27	9590-009-1305	14.0 ppb
2016-07-27	9590-010-1335	8.00 ppb
2016-07-27	9590-011-1655	19.0 ppb
2016-07-27	9590-012-1725	5.90 ppb
2016-07-27	9590-024-1645	15.0 ppb
2016-07-27	9590-025-1350	18.0 ppb
2016-07-27	9590-028-1710	13.0 ppb
2016-10-05	9590-006-1110	8.50 ppb
2016-10-05	9590-007-0900	4.80 ppb
2016-10-05	9590-008-1000	ND
2016-10-05	9590-009-0945	15.0 ppb
2016-10-05	9590-010-1015	10.00 ppb
2016-10-05	9590-011-1210	16.0 ppb
2016-10-05	9590-012-1230	14.0 ppb
2016-10-05	9590-024-1155	13.0 ppb
2016-10-05	9590-025-1030	17.0 ppb
2016-10-05	9590-028-1225	3.20 ppb
2017-01-11	9590-007-1040	7.40 ppb
2017-01-11	9590-008-1125	ND
2017-01-11	9590-009-1115	14.0 ppb
2017-01-11	9590-010-1135	12.0 ppb
2017-01-11	9590-011-1430	13.0 ppb
2017-01-11	9590-012-1500	18.0 ppb
2017-01-11	9590-024-1415	21.0 ppb
2017-01-11	9590-025-1155	29.0 ppb
2017-01-11	9590-028-1445	13.0 ppb
2017-02-01	9590-007-1050	16.0 ppb
2017-04-05	9590-006-1040	6.60 ppb
2017-04-05	9590-008-0912	12.0 ppb
2017-04-05	9590-009-0900	13.0 ppb
2017-04-05	9590-010-0928	15.0 ppb
2017-04-05	9590-011-1153	11.0 ppb
2017-04-05	9590-012-1214	14.0 ppb
2017-04-05	9590-024-1137	10.00 ppb
2017-04-05	9590-025-0950	15.0 ppb
2017-04-05	9590-028-1223	7.00 ppb
2017-07-20	9590-006-1330	8.70 ppb
2017-07-20	9590-007-1050	16.0 ppb
2017-07-20	9590-008-1141	19.0 ppb
2017-07-20	9590-009-1127	19.0 ppb
2017-07-20	9590-010-1155	18.0 ppb
2017-07-20	9590-011-1455	15.0 ppb
2017-07-20	9590-012-1515	18.0 ppb
2017-07-20	9590-024-1436	14.0 ppb
2017-07-20	9590-025-1216	20.0 ppb
2017-07-20	9590-028-1536	14.0 ppb
2017-10-04	9590-005-1154	5.00 ppb
2017-10-04	9590-007-0903	8.30 ppb
2017-10-04	9590-008-0959	14.0 ppb
2017-10-04	9590-009-0943	14.0 ppb
2017-10-04	9590-010-1014	12.0 ppb
2017-10-04	9590-011-1059	14.0 ppb
2017-10-04	9590-012-1034	13.0 ppb
2017-10-04	9590-024-1116	19.0 ppb
2017-10-04	9590-025-1138	14.0 ppb
2017-10-04	9590-028-1046	ND
2017-11-01	9590-006-1130	10.00 ppb
2017-11-01	9590-007-1010	7.20 ppb
2017-12-06	9590-007-1150	6.50 ppb
2018-01-10	9590-007-1230	8.80 ppb
2018-01-10	9590-008-1310	11.0 ppb
2018-01-10	9590-009-1255	13.0 ppb
2018-01-10	9590-010-1325	10.00 ppb
2018-01-10	9590-011-1525	12.0 ppb
2018-01-10	9590-012-1545	12.0 ppb
2018-01-10	9590-024-1515	14.0 ppb
2018-01-10	9590-025-1340	13.0 ppb
2018-01-10	9590-028-1535	ND
2018-04-11	9590-006-1430	3.50 ppb
2018-04-11	9590-008-1105	8.40 ppb
2018-04-11	9590-009-1045	13.0 ppb
2018-04-11	9590-010-1125	14.0 ppb
2018-04-11	9590-011-1230	11.0 ppb
2018-04-11	9590-012-1200	16.0 ppb
2018-04-11	9590-024-1245	12.0 ppb
2018-04-11	9590-025-1140	13.0 ppb
2018-04-11	9590-028-1215	ND
2018-05-02	9590-006-1205	7.00 ppb
2018-06-06	9590-006-1240	6.80 ppb
2018-06-06	9590-007-1040	6.20 ppb
2018-08-08	9590-006-1310	10.00 ppb
2018-08-08	9590-007-1000	5.30 ppb
2018-09-05	9590-006-1045	8.30 ppb
2018-09-05	9590-007-1230	4.50 ppb
2018-09-18	9590-008-1015	13.0 ppb
2018-09-18	9590-009-1000	12.0 ppb
2018-09-18	9590-010-1040	8.50 ppb
2018-09-18	9590-011-1225	10.00 ppb
2018-09-18	9590-012-1300	ND
2018-09-18	9590-024-1205	14.0 ppb
2018-09-18	9590-025-1100	10.00 ppb
2018-09-18	9590-028-1245	11.0 ppb
2018-10-03	3761-008-1040	ND
2018-10-03	3761-009-1025	12.0 ppb
2018-10-03	3761-010-1055	11.4 ppb
2018-10-03	3761-011-1240	13.1 ppb
2018-10-03	3761-012-1320	8.80 ppb
2018-10-03	3761-024-1220	17.5 ppb
2018-10-03	3761-025-1110	17.9 ppb
2018-10-03	3761-028-1305	11.6 ppb
2018-11-07	3761-006-1225	11.2 ppb
2018-11-07	3761-007-1020	2.10 ppb
2018-12-05	3761-006-1030	7.50 ppb
2019-01-09	3761-006-0940	3.50 ppb
2019-01-09	3761-008-1000	ND
2019-01-09	3761-009-0945	14.0 ppb
2019-01-09	3761-010-1010	8.60 ppb
2019-01-09	3761-011-1125	13.6 ppb
2019-01-09	3761-012-1150	13.5 ppb
2019-01-09	3761-024-1105	1.40 ppb
2019-01-09	3761-025-1030	16.3 ppb
2019-01-09	3761-028-1135	1.40 ppb
2019-03-06	3761-006-1020	9.20 ppb
2019-04-03	3761-006-1115	6.90 ppb
2019-04-03	3761-008-1030	1.000 ppb
2019-04-03	3761-009-1015	17.3 ppb
2019-04-03	3761-010-1045	18.5 ppb
2019-04-03	3761-011-1145	18.1 ppb
2019-04-03	3761-012-1215	20.7 ppb
2019-04-03	3761-024-1130	17.7 ppb
2019-04-03	3761-025-1055	18.5 ppb
2019-04-03	3761-028-1200	19.2 ppb
2019-05-01	3761-006-1040	7.30 ppb
2019-06-12	3761-006-1220	11.9 ppb
2019-06-12	3761-007-1000	4.60 ppb
2019-07-10	3761-008-0915	ND
2019-07-10	3761-009-0900	11.9 ppb
2019-07-10	3761-010-0930	8.70 ppb
2019-07-10	3761-011-1245	11.4 ppb
2019-07-10	3761-012-1315	8.50 ppb
2019-07-10	3761-024-1230	15.8 ppb
2019-07-10	3761-025-0950	11.7 ppb
2019-07-10	3761-028-1300	9.10 ppb
2019-08-07	3761-007-1010	4.30 ppb
2019-08-08	3761-006-1120	9.40 ppb
2019-09-04	3761-006-1050	12.7 ppb
2019-09-04	3761-007-0915	6.30 ppb
2019-10-02	3761-006-1100	8.30 ppb
2019-10-02	3761-007-0840	2.90 ppb
2019-10-02	3761-008-0935	ND
2019-10-02	3761-009-0910	12.8 ppb
2019-10-02	3761-010-0950	7.30 ppb
2019-10-02	3761-011-1200	11.0 ppb
2019-10-02	3761-012-1230	13.4 ppb
2019-10-02	3761-024-1140	16.3 ppb
2019-10-02	3761-025-1005	17.4 ppb
2019-10-02	3761-028-1215	ND
2019-11-06	3761-006-1045	9.10 ppb
2019-11-06	3761-007-0915	2.90 ppb
2019-12-04	3761-007-1150	14.0 ppb