International Benchmarking of Leakage from Water Reticulation Systems

Abstract

The IWA methodology of determining and comparing leakage in water distribution systems is now generally accepted as world's best practice in many countries around the globe. This paper will evaluate the methodology in terms of how it is being used in practical situations and present the results from a number of Water Utilities throughout the world. Various issues of specific relevance to the South African situation are also discussed and some new software developments are presented. Considerable progress has been made in the last few years regarding standard terminology and methodologies in terms of real losses from water distribution systems. In this regard efforts have been made worldwide by various individuals and organisations to assess levels of leakage and real losses in water distribution systems. This information is being collected and co-ordinated by one of the International Water Association's (IWA) sub-task forces and the preliminary results appear very promising. This paper provides a brief outline of the standard IWA methodology for assessing real losses and discusses the Infrastructure Leakage Index (ILI) in some detail. It also summarises the data collected and collated to date from numerous Water Utilities around the world. The data have been collected by various leakage management specialists who have been working together for many years as part of a larger IWA initiative. The results are presented in a clear and concise manner and are both interesting and informative. They provide Water Utility managers with a target against which they can compare their own performances regarding leakage from their systems. Issues and suggested solutions unique to South Africa are also discussed. Latest developments with regard to leakage assessment are presented including some brief details of new software and the internet based data management system currently being developed for use in South Africa.