Efficiency in the management of urban water services. What have we learned after four decades of research?

The analysis of efficiency in the management of urban water services offers valuable information both for the managers of this service and for public bodies in order to introduce improvements in business practices and in the design of public policies. Since the pioneering study carried out by Ford and Wardford (1969), there have been many attempts to follow this line of research. Due to the importance of the subject and the volume of publications in this field, we believe it is necessary to provide a balance of the work carried out over the last four decades. In this overview, we look at the main questions which have arisen over this period, we provide a synthesis of the results obtained and, finally, we point out some challenges for future research.