Economic level of leakage (ELL) calculation with limited data: an application in Zaragoza.

The Economic Level of Leakage is a systematic way for a water utility to estimate the optimum leakage level below which the costs of reducing leakage further exceed the benefits of saving water. This is applied in the city of Zaragoza in Spain, with initial estimates of ELL calculated using the Bursts and Background Estimates (BABE) approach with data from water supply records and measurements in a study area, together with empirical relationships from the literature. The analysis shows considerable scope for water loss recovery using active leakage control. The same approach could be used in other cities with limited data, to assess the potential benefits from water loss management.