Scale Economies, Technology and Technical Change in the Water Industry: Evidence from the English Water Only Sector

In this paper we estimate a variable cost function to analyze cost economies and technical change in the English water only sector over the 1995-2005 period. We jointly model the impact on costs of output, customers numbers and area size which allows us to consider both the vertical and horizontal (spatial) dimensions of water utilities' operations. Estimates suggest the existence of unexploited economies of output and customer density and small scale economies which appear to be increasing with population density. These findings suggest that moderate cost savings from prudent mergers could be expected; in particular, benefits of merging water utilities might be higher in more densely populated urban areas. Finally, technical change is found to be increasing over the sample period