The Combined Real Loss Index (CRLI): An Innovative Approach to Assessing Real Losses

Presentation by Daniel Zipperer at PI2025 in Poznań

At the 10th IWA Conference on Benchmarking, Performance Assessment and Regulation of Water Services (PI2025), organized by the International Water Association (IWA), aquabench shared practical insights into the use of the Combined Real Loss Index (CRLI) as a metric for assessing real losses in water supply networks. In his presentation, our Senior Project Manager Daniel Zipperer discussed the background, calculation method, and practical potential of this indicator – which has already seen initial real-world application in several countries.

Fair and Practical Assessment of Real Losses – Without Complex Pressure Data

Accurately assessing real losses in water supply networks remains a core challenge for utilities worldwide. While the Infrastructure Leakage Index (ILI) is widely recognized as a standard, its application often requires detailed pressure and infrastructure data – a barrier especially for small and medium-sized utilities. The Combined Real Loss Index (CRLI) offers a compelling alternative: By merging two established indicators into a density-independent formula, the CRLI provides a robust and easy-to-calculate performance metric for real losses – based entirely on long-term operational data that is typically available in most utilities.

Focus and Objective of the Conference Contribution

The presentation focused on introducing the CRLI concept and positioning it within the context of established performance indicators for real losses. Using structured operational data from utilities in Rhineland-Palatinate and Saarland (Germany), the presentation demonstrated how the CRLI can be applied in practice – and what potential it holds for enabling a simplified yet differentiated approach to water loss management.

Download the Full Presentation

You can download the full presentation as a PDF here.