Estimation of the economic level of water losses in water supply systems: a case study in northeastern Brazil

Abstract

Reducing water losses is a strategic challenge for water supply systems (WSS), particularly in regions characterized by operational heterogeneity, water scarcity, intermittent supply, and increasing production and distribution costs. Although the Economic Level of Losses (ELL) is widely recognized as a valuable decision-support tool, its application remains limited at regional scales and in systems with diverse structural and economic characteristics. This study proposes and applies a methodological approach to estimate the ELL, considering both real and apparent losses, in WSS with heterogeneous regional characteristics, using the state of Pernambuco, Brazil, as a case study. The methodology combined the Wyatt method with analysis of variance (ANOVA) to evaluate spatial and temporal variations among mesoregions. The results showed that four of the five mesoregions experienced reductions in water loss rates over the study period. However, the observed values generally exceeded the estimated ELL, which ranged from 20.72% to 22.58% at the state level. ANOVA indicated no statistically significant differences among the regional mean values of ELL and IN049; however, pairwise comparisons revealed important contrasts between specific mesoregions, highlighting the need for region-specific management strategies. The findings advance understanding of ELL behavior in WSS with high operational heterogeneity and demonstrate that its application at the regional scale can support more efficient, replicable water loss control policies in other regional contexts.