EWG's Tap Water Database — 2021 UPDATE


Chromium (hexavalent)

Dublin San Ramon Services District

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
20131.83 ppb660.250 ppb - 5.30 ppb
20142.29 ppb220.170 ppb - 4.40 ppb
201510.3 ppb669.00 ppb - 11.0 ppb
20169.50 ppb449.00 ppb - 10.00 ppb
201710.9 ppb11117.50 ppb - 13.0 ppb
201813.1 ppb7712.0 ppb - 14.0 ppb
201910.2 ppb996.50 ppb - 13.0 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
2013-05-07A3D2019-03A1.30 ppb
2013-05-07A3D2019-01A0.250 ppb
2013-08-05A3G2331-04A1.70 ppb
2013-08-05A3G2331-01A1.20 ppb
2013-11-06A3J2401-01A5.30 ppb
2013-11-06A3J2401-04A1.20 ppb
2014-02-04A4A1601-04A4.40 ppb
2014-02-04A4A1601-01A0.170 ppb