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EWG's Tap Water Database — 2021 UPDATE

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Chloromethane

City of San Marcos

Chloromethane is an industrial solvent, aerosol propellant and a refrigerant. It also forms as a byproduct of water disinfection. The EPA classifies chloromethane as possibly carcinogenic to humans.

 

56

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND170ND
2015ND140ND
2016ND60ND
2017ND70ND
2018ND60ND
2019ND60ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 2.69 ppb

The EWG Health Guideline of 2.69 ppb for chloromethane was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against cancer.

ppb = parts per billion

All test results

Date Lab ID Result
2014-03-12AC63077ND
2014-08-12AC63075ND
2014-08-12AC63087ND
2014-08-12AC63071ND
2014-08-12AC63073ND
2014-09-10A4H1453-16AND
2014-09-10A4H1453-13AND
2014-09-10A4H1453-19AND
2014-09-10A4H1453-04AND
2014-09-10A4H1453-01AND
2014-09-10A4H1453-10AND
2014-09-10A4H1453-07AND
2014-12-03A4K1048-05AND
2014-12-03A4K1048-17AND
2014-12-03A4K1048-08AND
2014-12-03A4K1048-11AND
2014-12-03A4K1048-14AND
2015-03-11A5B1481-10AND
2015-03-11A5B1474-04AND
2015-03-11A5B1481-07AND
2015-03-11A5B1481-13AND
2015-03-11A5B1474-01AND
2015-03-11A5B1481-04AND
2015-03-11A5B1481-01AND
2015-06-10AC95470ND
2015-06-10AC95468ND
2015-06-10AC95474ND
2015-06-10AC95472ND
2015-06-25A5F1429-04AND
2015-09-23AD08299ND
2015-09-23AD08303ND
2016-03-16AD29111ND
2016-09-16AD49839ND
2016-11-28AD59222ND
2016-11-28AD59220ND
2016-12-12AD61688ND
2016-12-12AD61664ND
2017-02-22AD71534ND
2017-05-03AD82468ND
2017-05-03AD82466ND
2017-05-03AD82462ND
2017-05-03AD82464ND
2017-07-12AD89095ND
2017-10-12AE00574ND
2018-01-25AE10574ND
2018-01-25AE10572ND
2018-01-25AE10638ND
2018-01-25AE10564ND
2018-04-11AE22067ND
2018-07-26AE34698ND
2019-01-16AE50162ND
2019-01-16AE50166ND
2019-01-16AE50168ND
2019-01-16AE50164ND
2019-04-16AE62552ND
2019-07-09AE73687ND