Non-Revenue Water (NRW) refers to treated water that enters a distribution system but does not generate revenue because it is lost through physical leakage, unauthorized consumption, inaccurate metering, or other operational inefficiencies. Around the world, NRW is considered one of the most important indicators of water utility performance because excessive water loss reduces income, increases operating costs, and limits the ability of utilities to expand access to safe drinking water.
Indonesia faces the same challenge. Many regional water companies continue to record NRW levels above the national performance target. In the case examined by the Universitas Negeri Gorontalo research team, the average NRW level reached 34.16 percent, exceeding the government's target of 30 percent. Even more concerning, water losses varied significantly among treatment plants, ranging from 15.53 percent to 59.51 percent, indicating that different service areas experience different underlying causes of water loss.
Rather than treating all causes equally, the researchers developed a systematic approach to determine which problems should receive immediate attention. Their analysis used the Analytical Hierarchy Process (AHP), a structured decision-making method that ranks multiple factors according to their relative importance.
The research combined 42 working days of field observations, conducted between January 19 and March 20, 2026, with operational reports, infrastructure documentation, interviews, and expert assessments from the technical management of PERUMDA City X. Seven water treatment plants representing different service zones were evaluated to identify operational conditions and infrastructure performance.
The findings revealed that technical problems dominate the causes of water loss, accounting for 55.8 percent of the total priority weight. Administrative issues ranked second at 26.3 percent, followed by operational factors at 12.2 percent, while authorized but unbilled water consumption represented only 5.7 percent of the overall problem.
Among the twelve identified sub-factors, three stood out as the most influential contributors to Non-Revenue Water:
- Network leakage contributed 35.88% of the total priority weight.
- Illegal water connections accounted for 19.04%.
- Pipe aging and corrosion represented 15.79%.
Together, these three factors explained 70.71 percent of the overall causes of water loss, demonstrating that a relatively small number of issues account for the majority of NRW within the studied utility.
The study also identified the absence of District Meter Areas (DMA) as an important operational weakness. DMA systems divide water distribution networks into smaller monitoring zones, allowing utilities to detect leaks more quickly and identify abnormal water consumption patterns. Without DMA implementation, locating leaks becomes more difficult, repair times become longer, and illegal connections are harder to detect, ultimately increasing water losses across the system.
Based on these findings, the Universitas Negeri Gorontalo researchers proposed a set of priority-based control strategies designed to maximize the effectiveness of limited financial and technical resources.
The highest priority is reducing network leakage through rapid-response maintenance teams, acoustic leak detection technology, phased DMA implementation, pressure management, and nighttime flow monitoring. These measures directly address the largest contributor to NRW.
The second priority focuses on illegal connections through regular inspections, customer legalization programs, installation of zonal master meters, regulatory enforcement, and public education campaigns aimed at improving compliance.
Longer-term investments include replacing aging pipelines according to infrastructure risk assessments, developing Geographic Information System (GIS)-based asset management databases, expanding DMA coverage with digital monitoring technologies such as SCADA and IoT, and implementing routine calibration or replacement of customer water meters older than five years.
Simulation results suggest that implementing these strategies together could reduce NRW by approximately 12.8 to 17.4 percentage points. If the current NRW level of 34.16 percent is reduced by that amount, PERUMDA City X could achieve an NRW level between 17 and 21 percent within three to five years, approaching internationally recognized efficiency benchmarks for water utilities.
According to Rudolf Simatupang and colleagues from Universitas Negeri Gorontalo, the research demonstrates that reducing Non-Revenue Water requires more than routine maintenance. Instead, utilities should prioritize interventions according to measurable evidence of their impact. By concentrating first on network leakage, illegal connections, and deteriorating infrastructure, water companies can allocate budgets more efficiently while achieving greater reductions in water loss.
The broader implications extend beyond operational performance. Lower NRW levels improve the financial stability of regional water utilities, enabling additional investment in infrastructure, broader access to clean water, and more reliable public services. For policymakers, the findings provide an evidence-based framework for designing NRW reduction programs. For utility managers, the study offers a practical roadmap for prioritizing investments under limited financial resources. The research may also serve as a valuable reference for engineering practitioners, infrastructure planners, and academics working on sustainable urban water management.
Author Profile
Rudolf Simatupang is a researcher from Universitas Negeri Gorontalo specializing in civil engineering, water distribution systems, infrastructure management, and Non-Revenue Water (NRW) control strategies. This study was conducted in collaboration with Haiqal Alief Djibran, Eko Adityawan Tumenggung Zees, and Jamal Darussalam Giu, who are also affiliated with Universitas Negeri Gorontalo. Together, the research team focuses on improving the efficiency, sustainability, and operational performance of regional drinking water utilities through evidence-based engineering and decision-support methods.
Source
Article Title: Determining Dominant Causes of Non-Revenue Water Using AHP and Priority-Based Control Strategies
Authors: Rudolf Simatupang, Haiqal Alief Djibran, Eko Adityawan Tumenggung Zees, Jamal Darussalam Giu
Affiliation: Universitas Negeri Gorontalo, Indonesia
Journal: Formosa Journal of Multidisciplinary Research (FJMR)
Volume 5, Issue 6 (2026), Pages 1783–1800
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