The fear of a cholera outbreak in Philadelphia in 1893 led to intense debate over how to manage the risk of an epidemic. Philadelphians largely agreed that the risk was spatial in nature, and that coping with the danger of cholera meant addressing the problem of the city's southeastern “slums.” But the meaning of this space was contested. Some reformers viewed it as a den of immorality, while others saw it as a site of injustice. The city government ignored both views, instead undertaking a technical reform by repaving the neighborhood's streets with asphalt. The episode demonstrates how competing understandings of risk and urban space yielded competing prescriptions for urban reform, and why technical reform came to be preferred over moral or economic reconstruction in the Progressive Era. Contrary to previous interpretations, Progressive reformers cannot be understood as simply “confident” or “anxious,” but as prioritizing certain risks while ignoring others.