Chloromethane

Walpole Water Department

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.

MORE ABOUT THIS CONTAMINANT

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	ND	10	0	ND
2015	ND	10	0	ND
2016	ND	8	0	ND
2017	ND	9	0	ND
2018	0.125 ppb	8	1	ND - 1.000 ppb
2019	ND	8	0	ND

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	Result
2014-02-03	ND
2014-02-03	ND
2014-05-05	ND
2014-05-05	ND
2014-08-04	ND
2014-08-04	ND
2014-11-03	ND
2014-11-03	ND
2014-12-08	ND
2014-12-08	ND
2015-02-02	ND
2015-02-02	ND
2015-05-04	ND
2015-05-04	ND
2015-05-14	ND
2015-05-14	ND
2015-08-03	ND
2015-08-03	ND
2015-11-02	ND
2015-11-02	ND
2016-02-01	ND
2016-02-01	ND
2016-05-16	ND
2016-05-16	ND
2016-08-01	ND
2016-08-01	ND
2016-11-07	ND
2016-11-07	ND
2017-02-06	ND
2017-02-06	ND
2017-05-01	ND
2017-05-01	ND
2017-08-07	ND
2017-08-07	ND
2017-08-23	ND
2017-11-06	ND
2017-11-06	ND
2018-02-05	1.000 ppb
2018-02-05	ND
2018-05-07	ND
2018-05-07	ND
2018-08-06	ND
2018-08-06	ND
2018-11-05	ND
2018-11-05	ND
2019-02-04	ND
2019-02-04	ND
2019-05-06	ND
2019-05-06	ND
2019-08-05	ND
2019-08-05	ND
2019-11-04	ND
2019-11-04	ND