Introduction Most of the world’s population now lives in urban areas. Getting water and using sanitation in cities can reproduce a range and intensity of inequalities, and opportunities for collective action that may not exist in the countryside. The urban poor are entangled with their cities’ economy and culture (Srivastava, 2014). Many work as domestic servants and guards for wealthier households, cleaners for retail spaces and offices, street hawkers and electricians, construction workers and more. The urban poor are a large part of a city’s labor force. They perform jobs no one else is willing to do, work long hours for low wages, and lower the living costs of those living outside low-income neighborhoods (Perlman, 1976: Ch. 8). They seek to survive and to improve their lives through these interactions, seeking education, employment, shelter, security and more. In Delhi and many other cities, the urban poor’s contributions to the formal city occur in the context of “constant, frequently enforced threats of displacement (through ‘slum demolitions’ for example), [and] their never-ending efforts to secure foothold within it (say, by purchasing fake identity cards)" (Srivastava 2014: xxxiv). In the wide range of capabilities sought by the urban poor, and the contexts of displacement, uncertainty and exclusion that they face, water and sanitation may appear to be just two among many exclusions. There is some evidence (Arputham, 2016; Devoto, et al., 2012; Swallow, 2005), nonetheless, that enhanced access to water and sanitation may be a high priority for the urban poor. I explore some possible reasons for this priority below. Some important aspects of urban water and sanitation include: - Providing infrastructure in some neighborhoods, and not others, leading to particular coping mechanisms and power inequalities. - Household water and sanitation replace irrigation as a principal focus of government attention and collective action. - The presence, absence and governance of municipal infrastructure are central to urban water and sanitation. - Water-borne disease transmission may be intensified in dense urban areas. This chapter has a particular focus on informal settlements, such as shantytowns, favelas, bustees and homeless encampments, the unregulated and sometimes illegal, often peri-urban and poorly provisioned settlements where many live and many dimensions of inequality and injustice are pronounced.