Operational Failures and Cost Implications in Water Distribution Networks: A Multi-Year Utility-Based Assessment

Water distribution networks are often assessed mainly through the number of recorded failures, although this indicator does not fully reflect the technical and economic burden imposed on utilities. This study proposes an Operational Failure-Cost Assessment (OFCA) method for transforming routine utility records into a cost-informed assessment of water network failures. The method was applied to an anonymized municipal water distribution network using failure records from 2015 to 2025, annual repair cost data from 2016 to 2024, and technical information on pipe type, material, and diameter structure. Failures were classified by pipe type, material, nominal diameter, and failure mechanism, while repair cost dynamics were evaluated using total annual repair expenditures and the average repair cost per recorded failure. During the common analysis period 2016–2024, the number of recorded failures decreased by 25.9%, whereas reported nominal annual repair costs increased by 77.9% and the average repair cost per recorded failure increased by approximately 140.3%. These results demonstrate that decreasing failure frequency does not necessarily imply decreasing repair cost pressure at the utility level. The proposed OFCA method provides a reproducible utility-level procedure that can be implemented even when event-level repair costs are not available. It supports maintenance planning, budgeting and prioritization of diagnostics, rehabilitation, and replacement activities.