Identification of a Suitable Method to Reduce Non-Revenue Water in Kotte Area in Sri Lanka
Keywords:
Apparent losses, Metering errors, Non-revenue water, Sri Lanka, Water supply managementAbstract
The National Water Supply and Drainage Board (NWSDB) of Sri Lanka faces persistent challenges due to Non-Revenue Water (NRW), defined as water produced but not generating income because of physical losses, metering errors, or unauthorized consumption. National NRW averages 26%, yet the Kotte area records a significantly higher rate of 32%, well above the NWSDB’s target of 24%.
This study investigates key contributors to NRW in Kotte, with a focus on cost-effective reduction strategies. Using root cause analysis, complaint code data, and correlation analysis, the research highlights that apparent losses, particularly meter reading errors, inaccessible premises, and defective meters, are the primary drivers of NRW in the region. While physical losses remain important, infrastructure replacement is capital-intensive, making administrative improvements a more feasible short-term priority.
To enhance rigor, the analysis integrates exploratory correlation with regression-based validation and discusses the need for predictive modeling to establish causal relationships. Findings recommend replacing defective meters, relocating meters for accessibility, and improving estimation methods for unrecorded readings. Financial feasibility analysis confirms that the proposed interventions are cost-effective, with positive Net Present Value (NPV).
The paper concludes that although preliminary results indicate administrative factors are significant, further validation using advanced statistical and simulation tools are required. A phased, data-driven approach is recommended to achieve sustainable NRW reduction in Kotte and provide a replicable model for other regions in Sri Lanka.
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