Adapting the economic level of leakage concept to include carbon emissions, and application with limited data

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. The concept can be adapted to include the economic costs of social and environmental externalities. The paper presents an approach for estimating the economic costs of greenhouse gas emissions and Incorporating these in the ELL calculation. This is applied in the city of Zaragoza in Spain, with initial estimates of ELL and externality costs calculated using data from water supply records and measurements in a study area, together with empirical relationships from the literature.