Australian ILIs update 2015

ILIs in Australia – update 2015

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, most 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 leak flow rates and burst frequencies in order to sustain water supplies.

Several advanced analytical approaches were developed as part of WSAA’s PPS-3 Asset Management Project ‘Leakage and Pressure Management’ 2008-11. These are summarized in a series of Reports and Case studies available to Utilities through WSAA’s Water Research Access Portal (WRAP) system at; type PPS-3 in the search facility to access Leakage and Pressure Management Stage 1, 2 & 3 Some of this work was influential in the initial evolution of predicting pressure:burst frequency relationships, see 2010 to 2011 references in

The information in the graph below was obtained from the National performance report 2013–14: urban water utilities .

ili aus a

All of the calculated ILIs for 2013-14 for the 63 Water Service Providers (WSPs) in the chart above, which are individually named and identified in the National Performance Report, are classified by number of properties (minimum 10,000). Data were independently audited, although there is one clearly anomalous result (WSP 1). For the purposes of the Global ILIs webpage, ILIs have been classified using Leakage Performance Categories (LPCs) A to D shown at the right hand side of the graph, see UARL and ILI for more information on LPCs.

Two-thirds of the Water Service Providers (and all of the largest WSPs with more than 100k properties) have achieved ILIs of 1.5 or less, which is an excellent performance by international standards; 80% of WSPs have ILIs within LPC Band A (Further loss reduction may be uneconomic unless there are shortages).

The ILI was specifically developed by the IWA Water Loss Task Force for national and international comparisons of technical leakage management. However; ILI is being calculated but not currently actively promoted in Australian National Performance Reports for the purpose it is designed for. It’s not only necessary to calculate the most appropriate performance indicators, but also to use them for the most appropriate purposes (see ). .

In Australian National Performance Reports, litres/service connection/day is currently used for both tracking and comparing leakage management performance of Australian WSPs. The recent EU Reference Document ‘Good Practices on Leakage Management’ Good Practices on Leakage Management – Main Report_Final.pdf confirmed that litres/connection/day is recommended for tracking performance in individual systems. However, the EU Reference Document also confirmed that ILI – not litres/service connection/day – should be used for technical performance comparisons between different systems because of widely different key characteristics (density of connections, length of service connections main to meter, average pressure).

ili combo

The Australian ILI data set has many ILIs close to 1.0, despite the large diversity in key system characteristics. This strongly supports the general validity of the UARL equation, published in 1999 to predict ‘how low could you go?’, ten years before such low leakage levels were being generally achieved in Australia and in many other countries. In a limited set of situations (see Paper 2014N, Presentation 2014M) the calculated real losses may be less than the UARL (resulting in ILIs less than 1.0) but ILIs less than 0.7 in WSAA systems should always be double checked for calculation errors.

The Global ILIs section of the LeaksSuite website is pleased to provide a forum where the excellent leakage management performance of the Australian WSPs can be compared on a level playing field with other leaders in leakage management.

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: 15th January 2016

Australian ILIs 2014 are available in the archive.