India faces severe water stress and, at the same time, over 40 billion liters of sewage remain untreated each day because cities do not have sewer networks and most municipal sewage treatment plants perform poorly. Smaller decentralized solutions are more effective and affordable for treating wastewater and reusing it productively, compared with large centralized sewerage systems.

We examine four cases—two decentralized sewage treatment plants and two fecal sludge management projects. They use different technologies to provide relatively quick-to-build, affordable, and effective wastewater management solutions, which towns, neighborhoods, campuses, and buildings can adopt to address water scarcity and pollution of water bodies in urban India.