Water is the cornerstone of public health. Yet many people living in Africa's cities face serious challenges obtaining an adequate supply of clean water. This situation, which poses significant public health concerns, promises only to grow in magnitude in the coming years as rapid urbanization and climate change meet head-on to further constrain urban water provision. This essay explores the relationship between water supply and health in urban Africa through the lens of water scarcity and health as political relationships as much as environmental or technical phenomena. By bringing infectious diseases like cholera and chronic ailments like kidney disease into the same frame of analysis, this essay also directs attention beyond the overwhelming public health focus on microbial contamination to emergent forms of water-related illness and injury that proceed unchecked.