Trichloroacetic acid

California Water Service (CWS) - Los Altos Suburban

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

193

Samples

Samples exceeding legal limit (MCL)

118

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	0.973 ppb	33	11	ND - 18.4 ppb
2015	1.41 ppb	32	18	ND - 4.60 ppb
2016	2.36 ppb	32	24	ND - 6.40 ppb
2017	3.63 ppb	32	23	ND - 14.0 ppb
2018	2.23 ppb	32	23	ND - 17.0 ppb
2019	1.67 ppb	32	19	ND - 5.40 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
2014-02-13	5810-900-1207	ND
2014-02-13	5810-901-1324	ND
2014-02-13	5810-902-1110	ND
2014-02-13	5810-903-1346	ND
2014-02-13	5810-904-1308	ND
2014-02-13	5810-905-1243	ND
2014-02-13	5810-906-1134	ND
2014-02-13	5810-907-1152	ND
2014-04-08	1610-903-0850	18.4 ppb
2014-05-15	5810-900-1336	1.20 ppb
2014-05-15	5810-901-1435	ND
2014-05-15	5810-902-1231	1.40 ppb
2014-05-15	5810-903-1459	1.90 ppb
2014-05-15	5810-904-1408	ND
2014-05-15	5810-905-1350	1.30 ppb
2014-05-15	5810-906-1248	1.80 ppb
2014-05-15	5810-907-1310	1.20 ppb
2014-08-07	5810-900-1228	1.10 ppb
2014-08-07	5810-901-1335	ND
2014-08-07	5810-902-1141	ND
2014-08-07	5810-903-1403	1.20 ppb
2014-08-07	5810-904-1429	ND
2014-08-07	5810-905-1246	1.10 ppb
2014-08-07	5810-906-1111	ND
2014-08-07	5810-907-1204	ND
2014-11-12	5810-900-1315	ND
2014-11-12	5810-901-1435	ND
2014-11-12	5810-902-1042	ND
2014-11-12	5810-903-1357	1.50 ppb
2014-11-12	5810-904-1332	ND
2014-11-12	5810-905-1252	ND
2014-11-12	5810-906-1144	ND
2014-11-12	5810-907-1220	ND
2015-02-09	5810-900-1619	ND
2015-02-09	5810-901-1333	ND
2015-02-09	5810-902-1705	ND
2015-02-09	5810-903-1304	1.80 ppb
2015-02-09	5810-904-1220	ND
2015-02-09	5810-905-1455	ND
2015-02-09	5810-906-1715	1.60 ppb
2015-02-09	5810-907-1550	ND
2015-05-14	5810-900-1246	4.20 ppb
2015-05-14	5810-901-1412	4.30 ppb
2015-05-14	5810-902-1058	3.90 ppb
2015-05-14	5810-903-1435	ND
2015-05-14	5810-904-1505	3.50 ppb
2015-05-14	5810-905-1225	4.00 ppb
2015-05-14	5810-906-1124	2.00 ppb
2015-05-14	5810-907-1147	4.60 ppb
2015-08-11	5810-900-1518	1.90 ppb
2015-08-11	5810-901-1200	1.90 ppb
2015-08-11	5810-902-1355	1.80 ppb
2015-08-11	5810-903-1323	1.80 ppb
2015-08-11	5810-904-1108	1.50 ppb
2015-08-11	5810-905-1600	1.80 ppb
2015-08-11	5810-906-1423	1.50 ppb
2015-08-11	5810-907-1533	1.80 ppb
2015-11-09	5810-900-1232	ND
2015-11-09	5810-901-1053	ND
2015-11-09	5810-902-1132	ND
2015-11-09	5810-903-1035	1.10 ppb
2015-11-09	5810-904-1114	ND
2015-11-09	5810-905-1435	ND
2015-11-09	5810-906-1321	ND
2015-11-09	5810-907-1256	ND
2016-02-09	5810-900-1041	1.40 ppb
2016-02-09	5810-901-1359	ND
2016-02-09	5810-902-1433	1.40 ppb
2016-02-09	5810-903-1114	6.40 ppb
2016-02-09	5810-904-1232	4.00 ppb
2016-02-09	5810-905-1005	1.40 ppb
2016-02-09	5810-906-1523	1.40 ppb
2016-02-09	5810-907-1458	1.20 ppb
2016-05-10	5810-901-1305	4.30 ppb
2016-05-10	5810-902-1145	4.90 ppb
2016-05-10	5810-906-1205	3.70 ppb
2016-05-10	5810-907-1230	3.70 ppb
2016-05-11	5810-900-1213	4.20 ppb
2016-05-11	5810-903-1145	5.50 ppb
2016-05-11	5810-904-1122	3.80 ppb
2016-05-11	5810-905-1244	4.30 ppb
2016-08-09	5810-900-1411	2.80 ppb
2016-08-09	5810-901-1312	3.00 ppb
2016-08-09	5810-902-1023	2.70 ppb
2016-08-09	5810-903-1330	2.70 ppb
2016-08-09	5810-904-1347	2.60 ppb
2016-08-09	5810-905-0940	2.80 ppb
2016-08-09	5810-906-1430	2.90 ppb
2016-08-09	5810-907-1007	2.80 ppb
2016-11-15	5810-900-1418	ND
2016-11-15	5810-901-1135	ND
2016-11-15	5810-902-1255	ND
2016-11-15	5810-903-1150	1.50 ppb
2016-11-15	5810-904-1233	ND
2016-11-15	5810-905-1445	ND
2016-11-15	5810-906-1325	ND
2016-11-15	5810-907-1348	ND
2017-02-14	5810-900-1320	ND
2017-02-14	5810-901-1205	ND
2017-02-14	5810-902-1505	ND
2017-02-14	5810-903-1240	2.80 ppb
2017-02-14	5810-904-1301	ND
2017-02-14	5810-905-1345	ND
2017-02-14	5810-906-1535	ND
2017-02-14	5810-907-1421	1.10 ppb
2017-05-09	5810-901-1120	ND
2017-05-09	5810-902-1240	6.90 ppb
2017-05-09	5810-903-1140	14.0 ppb
2017-05-09	5810-904-1209	11.0 ppb
2017-05-09	5810-905-1415	12.0 ppb
2017-05-09	5810-906-1300	3.80 ppb
2017-05-09	5810-907-1330	13.0 ppb
2017-05-11	5810-900-1529	9.60 ppb
2017-08-17	5810-900-1307	2.80 ppb
2017-08-17	5810-901-1138	ND
2017-08-17	5810-902-1339	2.80 ppb
2017-08-17	5810-903-1114	3.10 ppb
2017-08-17	5810-904-1159	2.20 ppb
2017-08-17	5810-905-1223	2.20 ppb
2017-08-17	5810-906-1403	2.80 ppb
2017-08-17	5810-907-1250	2.70 ppb
2017-11-14	5810-900-1330	2.20 ppb
2017-11-14	5810-901-1213	ND
2017-11-14	5810-902-1357	5.30 ppb
2017-11-14	5810-903-1152	8.50 ppb
2017-11-14	5810-904-1230	1.20 ppb
2017-11-14	5810-905-1004	2.10 ppb
2017-11-14	5810-906-1414	2.20 ppb
2017-11-14	5810-907-1309	1.70 ppb
2018-02-13	5810-901-1131	ND
2018-02-13	5810-902-1321	ND
2018-02-13	5810-906-1259	ND
2018-02-13	5810-907-1425	2.50 ppb
2018-02-14	5810-900-1713	1.70 ppb
2018-02-14	5810-903-1629	3.70 ppb
2018-02-14	5810-904-1646	2.10 ppb
2018-02-14	5810-905-1735	1.30 ppb
2018-05-15	5810-900-1435	1.20 ppb
2018-05-15	5810-901-1605	2.50 ppb
2018-05-15	5810-902-1009	3.80 ppb
2018-05-15	5810-903-1539	1.000 ppb
2018-05-15	5810-904-1505	1.10 ppb
2018-05-15	5810-905-1351	1.20 ppb
2018-05-15	5810-906-0926	17.0 ppb
2018-05-15	5810-907-1415	4.30 ppb
2018-08-14	5810-900-0940	3.00 ppb
2018-08-14	5810-901-1135	3.00 ppb
2018-08-14	5810-902-1010	2.90 ppb
2018-08-14	5810-903-1120	3.20 ppb
2018-08-14	5810-904-1100	3.00 ppb
2018-08-14	5810-905-0905	2.90 ppb
2018-08-14	5810-906-1030	2.90 ppb
2018-08-14	5810-907-0920	3.10 ppb
2018-11-15	5810-900-1305	ND
2018-11-15	5810-901-1425	ND
2018-11-15	5810-902-1120	ND
2018-11-15	5810-903-1400	2.50 ppb
2018-11-15	5810-904-1335	ND
2018-11-15	5810-905-1145	ND
2018-11-15	5810-906-1230	1.50 ppb
2018-11-15	5810-907-1205	ND
2019-02-12	5810-901-1625	ND
2019-02-12	5810-902-1245	4.70 ppb
2019-02-12	5810-906-1335	4.10 ppb
2019-02-12	5810-907-1220	5.10 ppb
2019-02-13	5810-900-1032	ND
2019-02-13	5810-903-0949	5.40 ppb
2019-02-13	5810-904-1146	2.30 ppb
2019-02-13	5810-905-1059	4.90 ppb
2019-05-14	5810-900-1516	ND
2019-05-14	5810-901-1429	1.90 ppb
2019-05-14	5810-902-1539	ND
2019-05-14	5810-903-1403	2.30 ppb
2019-05-14	5810-904-1343	2.10 ppb
2019-05-14	5810-905-1450	1.50 ppb
2019-05-14	5810-906-1556	2.10 ppb
2019-05-14	5810-907-1508	1.40 ppb
2019-08-13	5810-900-1211	ND
2019-08-13	5810-901-1455	ND
2019-08-13	5810-902-1227	2.00 ppb
2019-08-13	5810-903-1423	2.40 ppb
2019-08-13	5810-904-1506	1.60 ppb
2019-08-13	5810-905-1138	1.60 ppb
2019-08-13	5810-906-1241	1.80 ppb
2019-08-13	5810-907-1200	1.80 ppb
2019-11-14	5810-900-1352	ND
2019-11-14	5810-901-1127	ND
2019-11-14	5810-902-1248	ND
2019-11-14	5810-903-1104	ND
2019-11-14	5810-904-1030	ND
2019-11-14	5810-905-1423	ND
2019-11-14	5810-906-1233	4.50 ppb
2019-11-14	5810-907-1336	ND