Despite their fundamental importance, maximum contaminant level goals (MCLGs) remain overlooked in regulatory policy and litigation strategy. EPA establishes MCLGs for every contaminant under a national primary drinking water regulation, but these non-enforceable health goals rarely receive deserved attention. More troubling, as states increasingly adopt their own drinking water standards for emerging contaminants, many fail to establish corresponding MCLGs. This Comment addresses the importance of MCLGs in three contexts -- regulatory policy, water system management, and litigation strategy -- and offers recommendations for regulators, water suppliers, and courts.