Chromium-6 (Hexavalent chromium)

Chromium-6 (Hexavalent chromium) is a metal regulated in US drinking water. Industrial discharge from steel and pulp mills, electroplating, and leather tanning; erosion of natural deposits.

No federal MCL specific to chromium-6. It is regulated only as part of TOTAL chromium (MCL 0.1 mg/L = 100 ppb, SDWIS code 1020). California set a state MCL of 0.010 mg/L (10 ppb) for hexavalent chromium in 2024. Absence of a dedicated federal limit is itself the finding.

The subject of the 'Erin Brockovich' case. Ingestion is associated in animal studies with cancer of the digestive tract; long-term human health effects are still under study. Total chromium exposure is associated with allergic dermatitis.

EPA's enforcement data (SDWIS/ECHO) records zero violations of Chromium-6 (Hexavalent chromium)'s rule nationally. See this contaminant's regulatory status above for its current standard and compliance timeline — a zero count is not necessarily an all-clear.

Filter technologies certified to reduce Chromium-6 (Hexavalent chromium) include: reverse osmosis (NSF/ANSI 58), activated carbon (NSF/ANSI 53). Look for a filter independently certified against the specific NSF/ANSI standard for this contaminant — general "reduces contaminants" marketing claims are not the same as a contaminant-specific certification.