The provision of water and sanitation services (WSS) in developing countries has traditionally been the preserve of the state, but recently there has been a move towards greater private sector participation (PSP). While the potential economic benefits of PSP are well-known, the authors extensively discuss the environmental and social implications unique to the sector. The focus of the book is on the crucial role public authorities must continue to play to guarantee sustainability, levels of service and access to a variety of consumers. The authors show how these objectives are realised in very different ways - and not always successfully - in developing countries. The authors critically review the current literature and include new case studies from Manila, Buenos Aires, Cordoba, Abidjan and Mexico City. Private Firms and Public Water will be of interest to regulatory officials, economists, development professionals and scholars, as well as government, business and NGOs.