Protecting Pregnant Women and Children From Hexavalent Chromium Act of 2011 - Amends the Safe Drinking Water Act to require the Administrator of the Environmental Protection Agency (EPA) to: (1) publish a health advisory for hexavalent chromium that is fully protective of the health of vulnerable individuals (including pregnant women, infants, and children), taking into consideration body weight, exposure patterns, and all routes of exposure; and (2) establish a national primary drinking water regulation for hexavalent chromium that is protective of vulnerable individuals and the maximum contaminant level of which is as close to the maximum contaminant level goal for hexavalent chromium, and as protective of vulnerable individuals, as is feasible.