Australian ILIs 2014

ILIs in Australia – update 2014

The Water Services Association of Australia (WSAA), which represents the interests of the urban water industry, adopted the IWA Standard Water Balance and published an initial set of ILIs in WSAAfacts 2004.  During the next 8 years of extreme drought, almost all  Australian Water Service Providers (WSPs) had to use every means at their disposal, including recycled water, restrictions, intensive active leakage control and pressure management to reduce leakage in order to sustain water supplies.

All of the calculated ILIs for 64 named and identified WSPs in 2012/13 in the chart below, classified by National Water Commission by number of properties (minimum 10,000), have been independently audited, with just one anomalous result (WSP 1) requiring to be double checked. 22 WSPs achieved (and have maintained) ILIs of 0.9 to 1.1, with just a few (in locations where all leaks surface) achieving ILIs in the 0.6 to 0.8 range.

Australia ilis 3

In the Leakage Performance Categories A to D at the right hand side of the graph, introduced into World Bank Institute NRW Training Modules in 2005, Category A (ILI < 2) was split into two (A1 and A2) by WSAA in 2011 to encourage more than the current 2/3rds of WSPs to achieve ILIs of less than 1.5.  Categories A to D are briefly described as follows:

A: Further loss reduction may be uneconomic unless there are shortages

B: Possibilities for further improvement

C: Tolerable only if resources are plentiful and cheap

D: Inefficient use of resources, indicative of poor maintenance and system condition in general

Each Leakage Performance Category (LPC) is associated with a set of recommendations for leakage management activities appropriate to that LPC (see UARL and ILI).

This Australian data set demonstrates the general validity of the UARL equation, which was developed and first published in 1999 as a prediction of ‘how low could you go?’ before any substantial national or international body of leakage data as low as this was available.

In Section 8.3 of the NWC National Performance Report, litres per service connection/day is used for both tracking and comparing performance of Australian WSPs. It is easy (using the UARL equation) to demonstrate that litres/connection/day is excellent for tracking performance in individual systems, but not for comparisons between systems because of widely different key characteristics (density of connections, length of service connections main to meter, average pressure). The ILI performance indicator, which was specifically designed by the IWA Water Loss Task Force to take such differences into account for national and international comparisons of technical leakage management, is being calculated but not currently being used by NWC for the purpose it is designed for.

So is NWC unaware, or too modest to publicise, that ILI shows Australia as a world leader in leakage management for systems with more than 10,000 properties? Unfortunately, because low consumption is strongly promoted in Australia, and at least one Australian State Regulator continues to calculate leakage using the misleading ‘% of System Input Volume’, the excellent leakage management performance of the Australian WSPs is not currently being recognised (see

It’s not only necessary to use the most appropriate performance indicators, but also to use them for the most appropriate purpose.


Future Updates: Utilities with reliable calculated ILI values wishing to be represented in future summaries of National or Regional ILIs on this website are invited to Contact  WLRandA Ltd. Countries which already have sufficient ILI data to justify a separate entry within Global ILIs are also invited to Contact WLRandA.

Last updated: 29th June 2014