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EWG's Tap Water Database — 2019 UPDATE

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Dichloromethane (methylene chloride)

San Francisco Regional Water System

Methylene chloride is a common industrial solvent used for paint stripping, vapor degreasing, printing, electronics manufacturing and cleaning. It causes cancer and liver damage in animal studies. Read More.

Surface and groundwater can be contaminated with methylene chloride from industrial releases and landfill leaching. The EPA considers methylene chloride likely carcinogenic to people. Long-term ingestion of drinking water with methylene chloride contamination can cause liver damage and cancer. Occupational exposure to methylene chloride and other solvents has been linked with increased risk of miscarriage. Birth defects have also been observed in studies of laboratory animals exposed to methylene chloride during pregnancy.

Click here to read more about carcinogenic VOCs.

 

14

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND10ND
2013ND30ND
2014ND20ND
2015ND20ND
2016ND30ND
2017ND30ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 4 ppb

The EWG Health Guideline of 4 ppb for dichloromethane (methylene chloride) was defined 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 cancer.

EPA Maximum Contaminant
Level (MCL) 5 ppb

The legal limit for dichloromethane, established in 1992, was based on analytical detection limits at the time that the standard was set.

ppb = parts per billion

All test results

Date Lab ID Result
2012-06-139590-001-1045ND
2013-06-189553-016-0936ND
2013-06-189553-001-1110ND
2013-10-079553-015-1024ND
2014-06-179553-016-0904ND
2014-06-179553-001-1130ND
2015-05-279553-001-1235ND
2015-06-189553-015-0915ND
2016-06-149553-015-1231ND
2016-06-149553-001-1105ND
2016-06-219553-016-1055ND
2017-06-199553-015-1100ND
2017-06-199553-001-1025ND
2017-06-199553-016-0953ND