4.1 INTRODUCTION

Compiling a reliable water audit or water balance is the critical first step in managing losses in public water supplies.

Just as businesses routinely prepare statements of debits and credits for their customers and banks provide statements of monies flowing into and out of accounts, the water audit displays how quantities of water flow into and out of the distribution system and to the customer. Yet, as essential and commonplace as financial audits are to the world of commerce, water audits have been surprisingly uncommon in public water supply throughout most of the world. In places where the intrinsic value of water has not been recognized, little motivation has existed to prompt requirements for auditing and sound assessments of water loss performance. As water is becoming a more valued commodity, however, this picture is beginning to change.

Throughout the 1990s, efforts were made to develop a rational, standardized water audit methodology and water loss performance indicators. Part of the motivation for this work was the focus on demand management and the wise use of water in England and Wales, which was driven by competition, drought-related water shortages, and other factors. In the late 1990s the International Water Association (IWA) initiated a large-scale effort to assess water supply operations, which resulted in the publication of Performance Indicators for Water Supply Services in 2000.1 While this initiative included various groups assessing all aspects of water supply operations, the Task Force on Water Loss worked specifically to devise...