Performance indicators for small- and medium-sized water supply systems: a review

Water supply systems (WSSs) are one of the most important and expensive core public infrastructures. The primary objective of a water supply utility is to have this valuable asset operate at its maximum possible efficiency with minimum cost throughout its design period. To achieve this objective, the first step is to evaluate the existing efficiency of all the components of the WSS using suitable performance indicators (PIs). Various agencies and organizations worldwide have developed detailed performance evaluation frameworks including several indicators to comprehensively cover all the aspects (e. g., physical asset, staffing, operational, customer satisfaction, economical) of the WSSs. Most of these frameworks and indicators have been developed for large-sized WSSs. Small-and medium-sized water supply systems (SM-WSSs) have specific performance-related issues, ranging from difficulties in collecting the data required to use the available systems of PIs to lack of skilled personnel and financial resources for efficient operations. A comprehensive review of the literature has been carried out to assess the suitability of reported performance evaluation systems for SM-WSSs in terms of their simplicity (easy and simple data requirements) and comprehensiveness (i.e., all the components of a WSS). This review also evaluates the individual PI with respect to its understandability, measurability, and comparability (i.e., within and across utility comparisons). On the basis of this detailed review, a conceptual performance evaluation system for SM-WSSs, consisting of a list of PIs grouped into their respective categories, has been proposed. The proposed system provides a stepwise approach, starting the performance evaluation process with the most significant and easy to measure PIs for small-sized WSSs and moving to a relatively complex set of indicators for SM-WSS depending on the availability of resources and specific operating conditions.