Using water loss performance indicators to support regulation and planning in real water distribution systems

Water loss performance indicators (WLPIs) are used worldwide by regulatory bodies and water utilities to assess the quality of water infrastructure management and drive investments in leakage reduction. In recent years, the digital transition in the water sector has motivated the implementation of structured digital water strategies to make management processes more efficient, combining improved data collection, analysis tools and advanced physically based modelling. WLPIs should be part of such strategy to direct investments towards efficient, replicable, scalable and robust plans. This work considers the most adopted WLPIs from the perspective of their use within the water regulation framework and to support water utilities during the progressive implementation of leakage reduction actions. The primary purpose is to analyse WLPIs’ capability to support assessment and decisions at the two levels, i.e. water utilities and regulators. The analysis performed on real systems confirms that the percentage indicator is misleading for both regulatory and planning purposes. The leakage density indicator can be helpful to evaluate the combined effect of pressure and asset management on leakage volume. Still, it should be used in conjunction with the new Asset Management Support Indicator (AMSI) to achieve efficient action plans at operational, tactical and strategic time horizons.