For many nations around the world, shale gas represents an opportunity to strengthen energy security while cutting emissions. In fact, shale gas adds 47 percent to the world's natural gas reserves. But as governments and businesses explore this new and abundant resource, freshwater availability is a key challenge they must address. In this study, the World Resources Institute (WRI) provides unprecedented global information on freshwater availability for governments and businesses considering shale development. This report draws on WRI's Aqueduct Water Risk Atlas to identify the key locations, globally and with a focus on 11 countries, where shale gas and tight oil extraction might face the greatest water challenges. In these areas government policies will be needed to guarantee water security, protect the environment, and avoid business risks, if shale energy is developed.