Graziano ABRATE
Ceris-CNR e HERMES

Giovanni FRAQUELLI
Università del Piemonte Orientale, Ceris-CNR e HERMES

Abstract: The Piano d’Ambito is a fundamental instrument for the planning and the management of the integrated water service. Given the evolution of demand, it allows local authorities to define the tariff structure necessary to grant the equilibrium between costs and revenues. Analysing an unbalanced panel data concerning 46 Piani d’Ambito observed for 5 to 30 years (1024 total observations), the objective is to verify if the water consumption forecasts are coherent with the available empirical literature. The econometric analysis highlights an implicit demand elasticity equal to 0, and an unjustified growth of per-capita levels of water consumption. With the formulation of more realistic demand  scenarios, the problem of budget equilibrium emerges for almost all considered Ambitos, with obvious consequences on planned investments or, alternatively, on tariffs. Under alternative hypothesis, we estimate on average a shortcoming of revenues from 10% to 16% with respect to the budget plans.