EWG's Tap Water Database — 2021 UPDATE


Chromium (hexavalent)

First Mutual Water System

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
201417.5 ppb2217.0 ppb - 18.0 ppb
201516.4 ppb447.60 ppb - 29.0 ppb
201625.5 ppb4418.0 ppb - 46.0 ppb
201718.3 ppb4411.0 ppb - 26.0 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
2014-09-025806-001-143817.0 ppb
2014-12-035806-001-092418.0 ppb
2015-03-275806-001-14247.60 ppb
2015-04-065806-001-142312.0 ppb
2015-07-065806-001-115217.0 ppb
2015-10-065806-001-102029.0 ppb
2016-01-055806-001-105646.0 ppb
2016-04-055806-001-130918.0 ppb
2016-07-055806-001-141019.0 ppb
2016-10-115806-001-143819.0 ppb
2017-01-165806-001-152411.0 ppb
2017-04-055806-001-151118.0 ppb
2017-07-125806-001-100018.0 ppb
2017-10-025806-001-051326.0 ppb