There has been a number of inquiries regarding Chromium 6 in Madison's water supply. The Madison Water Utility follows the guidance from state and federal agencies. The following link from the American Water Works Association has helpful information on this important topic.
Madison’s Health Officer and Foreman of the Water Utility point out that Madison's water tests show chromium levels well below the guidelines.
It is important to compare apples to apples. In this case, it is important to understand the difference between mg/L versus ppb (mg/l is milligrams per liter and ppb is parts per billion). One part per billion is the equivalent of one second in every 32 years.
The United States Environmental Protection Agency (USEPA) regulates TOTAL chromium in drinking water and has set a 'Maximum Contaminant Level' (MCL) of 0.1 mg/L (milligrams per liter), or 100 ppb (parts per billion). The World Health Organization (WHO) has adopted a stricter guideline for total chromium of 0.05 mg/L, or 50 ppb. Madison's most recent water test showed total chromium levels of 1.44 ppb, well below the universal standard.