A transformation took place during British imperial rule in Egypt whereby Cairo became an object of governance and the site of technological and social intervention after two decades of marginality to colonial policy. My project examines what caused this transformation, how it shaped the spatial and social landscape of a booming metropolis, and how these developments produced opportunities, contradictions, and spaces for contestation and opposition. The regime attempted to entrench its power by creating a well-oiled machine for cultivating, transporting, and exporting cotton, Egypt’s most important cash crop. However, cholera epidemics and a housing crisis caused by a cycle of boom and bust at a time of influx of foreign capital forced the colonial administration to turn its attention to Egyptian cities, particularly Cairo and Alexandria. In response, the imperial regime mobilized its scientific and technological expertise to fashion a program of urban infrastructural organization, particularly in the domains of water provisioning and sanitation. The flows of clean and foul waters and the flows of power were materially linked through pipes. These infrastructures were also sites of contestation over knowledge. This project interrogates the logics and epistemologies of expert designers and managers of urban infrastructures including engineers and public hygienists. It underscores how experts reflected on their knowledge and its limits and on the relationship between technology and the social world it aimed to pattern. It probes how the colonized viewed, appropriated, and subverted everyday technologies and how these complex encounters engendered new subjectivities. And it draws lessons from the failures of imperial administrations to understand and reorder the colonies through technology.