EWG's Tap Water Database — 2019 UPDATE


Chromium (hexavalent)

Washington Aqueduct Division

Chromium (hexavalent) is a carcinogen that commonly contaminates American drinking water. Chromium (hexavalent) in drinking water may be due to industrial pollution or natural occurrences in mineral deposits and groundwater. Read more about chromium (hexavalent).





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20120.0688 ppb880.0400 ppb - 0.1000 ppb
20130.0688 ppb880.0400 ppb - 0.1000 ppb
20140.0850 ppb880.0600 ppb - 0.1000 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.02 ppb

The EWG Health Guideline of 0.02 ppb for chromium (hexavalent) 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.

ppb = parts per billion

All test results

Date Lab ID Result
2012-02-01McMillan0.0700 ppb
2012-02-01Dalecarlia0.1000 ppb
2012-05-01Dalecarlia0.0700 ppb
2012-05-01McMillan0.0400 ppb
2012-08-01Dalecarlia0.0700 ppb
2012-08-01McMillan0.0500 ppb
2012-11-01Dalecarlia0.0900 ppb
2012-11-01McMillan0.0600 ppb
2013-02-01McMillan0.0500 ppb
2013-02-01Dalecarlia0.1000 ppb
2013-05-01Dalecarlia0.0600 ppb
2013-05-01McMillan0.0400 ppb
2013-08-01Dalecarlia0.0800 ppb
2013-08-01McMillan0.0500 ppb
2013-11-01Dalecarlia0.0900 ppb
2013-11-01McMillan0.0800 ppb
2014-01-01Dalecarlia0.0800 ppb
2014-01-01McMillan0.0900 ppb
2014-04-01Dalecarlia0.0800 ppb
2014-04-01McMillan0.0900 ppb
2014-07-01Dalecarlia0.1000 ppb
2014-07-01McMillan0.1000 ppb
2014-10-01Dalecarlia0.0800 ppb
2014-10-01McMillan0.0600 ppb