Key drivers of non-revenue water in developing countries: Insights from a multilevel study in Brazil

The increasing pressure on water resources has intensified the need to improve water supply efficiency, particularly by minimizing water loss. Non-revenue water (NRW) remains a critical issue in Brazil, with high loss levels impacting both financial sustainability and water security. This study employs a two-level hierarchical linear model (HLM2) to analyze NRW drivers in 310 Brazilian municipalities from 2017 to 2021. Ten factors that could influence water loss in the country were selected based on previous literature, and our results indicate that only four of them were statistically significant: population size, share of residential consumers, network length, and utility ownership. Municipalities with larger urban populations and longer distribution networks exhibited higher NRW levels, while a higher share of residential consumers correlated with lower NRW. Additionally, private utilities demonstrated lower water losses compared to public ones, likely due to stronger efficiency incentives. These findings highlight that the factors influencing NRW in Brazil differ from those commonly reported in studies based on developed countries. Therefore, policies designed to reduce NRW must consider regional specificities rather than relying solely on international benchmarks, which usually refer to developed countries. This study provides empirical evidence to support targeted interventions, helping water utilities and policymakers develop more effective NRW reduction strategies.