Over 1 billion people lack adequate access to clean and safe water. Even many of us who do enjoy basic water security live in areas subject to climate variability or population pressures that result in episodic water shortages, unsustainable reliance on groundwater, and/or pollution of available freshwater resources and environments. These pressures exist across the full range of spatial scales, from neighborhood to global, and a wide spectrum of development circumstances. In this context, understanding and informing effective water policy requires a technical understanding of hydrologic systems and engagement with the diverse social, economic, and political concerns that weigh on water management decisions. The JHU Global Water Program strives to educate, inform, and innovate on critical issues in water policy.