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EWG's Tap Water Database — 2021 UPDATE

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Monochloroacetic acid

California Water Service - San Mateo

Monochloroacetic 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

 

192

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.325 ppb324ND - 3.00 ppb
2015ND320ND
20160.600 ppb328ND - 3.00 ppb
20171.13 ppb3215ND - 3.00 ppb
20180.613 ppb328ND - 3.50 ppb
20190.897 ppb3212ND - 2.90 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 53 ppb

The EWG Health Guideline of 53 ppb for monochloroacetic 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.. This health guideline protects against system toxicity.

ppb = parts per billion

All test results

Date Lab ID Result
2014-02-055810-900-1205ND
2014-02-055810-901-11202.50 ppb
2014-02-055810-902-1105ND
2014-02-055810-903-0945ND
2014-02-055810-904-1140ND
2014-02-055810-905-1000ND
2014-02-055810-906-1020ND
2014-02-055810-907-1225ND
2014-05-075810-900-1315ND
2014-05-075810-901-1645ND
2014-05-075810-902-1630ND
2014-05-075810-903-1540ND
2014-05-075810-904-1705ND
2014-05-075810-905-16003.00 ppb
2014-05-075810-906-16342.10 ppb
2014-05-075810-907-14552.80 ppb
2014-08-065810-900-1000ND
2014-08-065810-901-1100ND
2014-08-065810-902-1115ND
2014-08-065810-903-1250ND
2014-08-065810-904-1025ND
2014-08-065810-905-1005ND
2014-08-065810-906-1140ND
2014-08-065810-907-1055ND
2014-11-035810-900-1300ND
2014-11-035810-901-1245ND
2014-11-035810-902-1230ND
2014-11-035810-903-1110ND
2014-11-035810-904-1350ND
2014-11-035810-905-1125ND
2014-11-035810-906-1335ND
2014-11-035810-907-1320ND
2015-02-045810-900-1420ND
2015-02-045810-901-1520ND
2015-02-045810-902-1540ND
2015-02-045810-903-1250ND
2015-02-045810-904-1340ND
2015-02-045810-905-1310ND
2015-02-045810-906-1500ND
2015-02-045810-907-1440ND
2015-05-065810-900-0950ND
2015-05-065810-901-1630ND
2015-05-065810-902-1615ND
2015-05-065810-903-1225ND
2015-05-065810-904-0900ND
2015-05-065810-905-1235ND
2015-05-065810-906-1135ND
2015-05-065810-907-1055ND
2015-08-045810-900-1000ND
2015-08-045810-901-0950ND
2015-08-045810-902-0930ND
2015-08-045810-903-1055ND
2015-08-045810-904-0900ND
2015-08-045810-905-1110ND
2015-08-045810-906-1125ND
2015-08-045810-907-1150ND
2015-11-035810-900-1145ND
2015-11-035810-901-1255ND
2015-11-035810-902-1240ND
2015-11-035810-903-1315ND
2015-11-035810-904-1350ND
2015-11-035810-905-1325ND
2015-11-035810-906-1125ND
2015-12-095810-907-0845ND
2016-02-025810-900-15302.30 ppb
2016-02-025810-901-1420ND
2016-02-025810-902-1405ND
2016-02-025810-903-15002.30 ppb
2016-02-025810-904-14402.10 ppb
2016-02-025810-905-15152.30 ppb
2016-02-025810-906-13302.30 ppb
2016-02-025810-907-13502.20 ppb
2016-05-025810-900-1130ND
2016-05-025810-901-0930ND
2016-05-025810-902-0945ND
2016-05-025810-903-1020ND
2016-05-025810-904-0910ND
2016-05-025810-905-1030ND
2016-05-025810-906-1110ND
2016-05-025810-907-1050ND
2016-08-025810-900-1315ND
2016-08-025810-901-1130ND
2016-08-025810-902-1115ND
2016-08-025810-903-12452.70 ppb
2016-08-025810-904-1220ND
2016-08-025810-905-12553.00 ppb
2016-08-025810-906-1400ND
2016-08-025810-907-1335ND
2016-11-075810-900-0945ND
2016-11-075810-901-0855ND
2016-11-075810-902-0915ND
2016-11-075810-903-1010ND
2016-11-075810-904-0825ND
2016-11-075810-905-1040ND
2016-11-075810-906-1120ND
2016-11-095810-907-0755ND
2017-02-065810-900-1045ND
2017-02-065810-901-1245ND
2017-02-065810-902-1200ND
2017-02-065810-903-1005ND
2017-02-065810-904-1010ND
2017-02-065810-905-10202.10 ppb
2017-02-065810-906-1115ND
2017-02-065810-907-1100ND
2017-05-015810-900-15102.80 ppb
2017-05-015810-901-1130ND
2017-05-015810-902-1145ND
2017-05-015810-903-14403.00 ppb
2017-05-015810-904-11102.10 ppb
2017-05-015810-905-14552.80 ppb
2017-05-015810-906-1030ND
2017-05-015810-907-10453.00 ppb
2017-08-095810-900-08202.20 ppb
2017-08-095810-901-1140ND
2017-08-095810-902-11502.20 ppb
2017-08-095810-903-13152.90 ppb
2017-08-095810-904-07402.00 ppb
2017-08-095810-905-15302.30 ppb
2017-08-095810-906-1205ND
2017-08-095810-907-09002.30 ppb
2017-11-085810-900-10332.10 ppb
2017-11-085810-901-1005ND
2017-11-085810-902-0930ND
2017-11-085810-903-1101ND
2017-11-085810-904-0830ND
2017-11-085810-905-1030ND
2017-11-085810-906-11272.10 ppb
2017-11-085810-907-11522.20 ppb
2018-02-055810-900-1250ND
2018-02-055810-901-1220ND
2018-02-055810-902-1205ND
2018-02-055810-903-1020ND
2018-02-055810-904-1235ND
2018-02-055810-905-1315ND
2018-02-055810-906-09352.00 ppb
2018-02-055810-907-0955ND
2018-05-075810-900-12103.50 ppb
2018-05-075810-901-1330ND
2018-05-075810-902-1315ND
2018-05-075810-903-1140ND
2018-05-075810-904-1350ND
2018-05-075810-905-1155ND
2018-05-075810-906-14252.10 ppb
2018-05-075810-907-14352.90 ppb
2018-08-065810-900-09002.00 ppb
2018-08-065810-901-08302.80 ppb
2018-08-065810-902-0840ND
2018-08-065810-903-09102.20 ppb
2018-08-065810-904-0810ND
2018-08-065810-905-0920ND
2018-08-065810-906-0950ND
2018-08-065810-907-09352.10 ppb
2018-11-055810-900-1110ND
2018-11-055810-901-1135ND
2018-11-055810-902-1125ND
2018-11-055810-903-1025ND
2018-11-055810-904-1055ND
2018-11-055810-905-1035ND
2018-11-055810-906-0950ND
2018-11-055810-907-1005ND
2019-02-065810-900-1010ND
2019-02-065810-901-1110ND
2019-02-065810-902-1100ND
2019-02-065810-903-0945ND
2019-02-065810-904-1125ND
2019-02-065810-905-0955ND
2019-02-065810-906-1045ND
2019-02-065810-907-1025ND
2019-05-075810-900-11102.10 ppb
2019-05-075810-901-1015ND
2019-05-075810-902-10002.60 ppb
2019-05-075810-903-09252.00 ppb
2019-05-075810-904-1030ND
2019-05-075810-905-09352.20 ppb
2019-05-075810-906-1145ND
2019-05-075810-907-1125ND
2019-08-065810-900-08202.60 ppb
2019-08-065810-901-10002.20 ppb
2019-08-065810-902-10102.40 ppb
2019-08-065810-903-07452.90 ppb
2019-08-065810-904-09402.30 ppb
2019-08-065810-905-08002.70 ppb
2019-08-065810-906-10302.40 ppb
2019-08-065810-907-08352.30 ppb
2019-11-055810-900-1145ND
2019-11-055810-901-0915ND
2019-11-055810-902-0925ND
2019-11-055810-903-1125ND
2019-11-055810-904-0855ND
2019-11-055810-905-1130ND
2019-11-055810-906-1215ND
2019-11-055810-907-1200ND