A mathematical model to evaluate apparent losses due to water meter under-registration in a urban distribution network

Apparent losses due to water meter under-registration were evaluated by means of a mathematical model able to analyse the complexity of supply systems with private tanks. This supply scheme is very common in the Mediterranean where water shortage often happens and the intermittent water supply is a common practice. A demand model that reproduces the effect of private tank and an apparent losses module were developed and coupled with an hydraulic network model based on Enhanced Global Gradient Algorithm (EGGA). In addition a pressure reducing valve (PRV) model was coupled. PRVs are often used by water utilities to control the pressure and reduce background losses. These practices could influence the performance of water meters. The comprehensive model was applied to a real case study in Palermo (Italy). The proposed modelling approach was used to identify regions of the network with high apparent losses. Furthermore, the model may be used to predict the results of a water meter replacement plan and of the installation of devices that could affect apparent losses.