Chromium-6 (or hexavalent chromium) has recently been discovered in limited amounts in some water supplies. Chromium-6 is suspected of being a carcinogen, and should not be ingested at amounts above the federally mandated limits. We have never been alarmists, but if you are concerned about the quality of the water you drink, you might want to consider a reverse osmosis system. Reverse Osmosis is the only readily available system that reduces Chromium-6.