Cities are often seen as incubators for enterprise and innovation. However, in this urbanisation era, we seem to suffer from a lack of imagination on how to handle the many environmental problems associated with expanding cities. This is especially true in the case of the peri-urban interface (PUI), a geographical and conceptual landscape with which the city core often has a contentious relationship. In this chapter, we look at the complex linkages between water and waste in the PUIs of two metropolitan cities: Bengaluru and Kolkata. We look at two water systems: Kannuru lake in Bengaluru and Kolkata’s wetlands. Kannuru is a freshwater lake that supported traditional livelihoods and subsistence use by local communities, while Kolkata’s peri-urban wetlands not only served as the city’s natural sewage treatment plant but also enabled agriculture and aquaculture. Urbanization has adversely impacted both these water systems. Kannuru lake is threatened by a landfill on its periphery, while sewage-based farming and fisheries in Kolkata’s wetlands have been impacted by changes in land use and composition of sewage. We unravel the complexity in the waste-water relationship, where waste is seen as a pollutant in one and as a nutrient in the other. We attempt to understand how we can re-envision waste and water linkages in the PUIs of expanding cities if India needs to move towards a sustainable future.