Water is a brutal delineator of social power which has at various times worked to either foster greater urban cohesion or generate new forms of political conflict'. In the paper which follows, Matthew Gandy explores this statement by looking at the expansion of urban water systems since the chaos of the nineteenth-century industrial city. In this early period, the relationship between water and urban space can be understood by the emergence of what he calls the 'bacteriological city', defined by features such as new moral geographies and modes of social discipline based upon ideologies of cleanliness, a move away from laissez-faire policies towards a technocratic and rational model of municipal managerialism, and a connection between urban infrastructures and citizenship rights. Gandy goes on to discuss that while many cities never ultimately conformed to this model, the last thirty years has seen a fundamental move away from the bacteriological city to a more diffuse, fragmentary and polarized urban technological landscape. Characteristics here include declining investment in urban infrastructures, a desire to meet shareholder rather than wider public needs, oligopolistic structures amongst providers, the marketisation of goods such as water, increased health scares and mistrust from consumers, and polarisation of the quality of service provision. For Gandy, these shifts are better understood by more relational, hybridised, rather than functional-linear, notions of urban metabolic systems.