Recent testing of 35 cities across the country has revealed that at least 31 of those cities could have elevated levels of the contaminant hexavalent chromium, also known as Chromium-6. More information on the report can be found in this CNN article.
Reports have indicated that simply drinking bottled water will not safeguard against ingesting chromium-6 as many bottled water companies use municipal water supplies to fill their bottles. Filtering tap water is also not guaranteed to reduce chromium-6 unless you are using a system that is certified to reduce chromium. Many reverse osmosis systems can reduce chromium-6 as well as a variety of other contaminants from drinking water.