Amid the talk of looming “water wars,” a less dramatic—but more immediate—link between water and violence is often ignored: the violence engendered by poor governance of water resources. Policies to expand water supplies, develop hydroelectric power, alter freshwater ecosystems, or change the terms of access to water can have devastating impacts on the livelihoods, cultures, and human rights of local communities. As these communities learn to voice their grievances, build networks across borders, and connect with human rights and environmental activists, once-local conflicts become international disputes. As a result, policymakers at all levels are being forced to rethink water’s role in development. To ensure water security in the 21st century, social conflicts over water must be managed in ways that accommodate the full range of people affected by water development projects.