The provision of a safe and reliable water supply is a major challenge for the world's growing urban populations. This book investigates the implications of different developments in water technology and infrastructure for urban sustainability and the relationship between cities and nature. The book begins by outlining five frameworks for analysing water technologies and systems - sustainable development, ecological modernisation, socio-technical systems, political ecology and radical ecology. It then analyses in detail what the sustainability implications are of different technical developments in water systems, specifically: demand management, sanitation, urban drainage, water reuse and desalination. The main purpose of the book is to draw out the social, political and ethical implications of technical changes that are occurring in urban water systems around the world, with positive and negative impacts on sustainability. Distinguished from existing social science analysis due to its attention to the engineering details of the technology, this book will be of use to a wide audience, including students on water management courses, engineering students and researchers, urban geographers and planners interested in sustainability, infrastructure and critical ecology.