Impact of Transitioning to Treated Water on Diarrhea Reduction: A Cross-Sectional and Ecological Study in Southwestern Goiás, Brazil

Access to safe drinking water is a global challenge, with significant disparities affecting public health and quality of life. This study evaluated the relationship between specific water parameters, public satisfaction with treated water, and diarrhea incidence in Southwestern Goiás, Brazil. The objectives were (1) to assess water parameters, including aluminum, iron, manganese, pH, hardness, fecal coliforms, and turbidity, in samples from springs, streams, and municipal supplies; (2) to evaluate residents' satisfaction with municipal water and their reliance on untreated water sources; and (3) to analyze the impact of transitioning from untreated to treated water following the closure of a spring in 2017 on diarrheal diseases. A longitudinal observational study reviewed diarrhea cases from 2013 to 2019. Treated water met potability standards, while untreated springs showed significant contamination. Dissatisfaction with treated water correlated strongly with continued reliance on untreated springs (<i>p</i> < 0.05), increasing the diarrhea risk nearly ninefold (OR = 8.78; 95% CI = 4.37-18.29). The findings underscore the importance of transitioning to treated water for mitigating diarrheal diseases and enhancing public trust in water safety. This study provides a replicable and scalable approach for improving water sanitation management, addressing waterborne diseases, and supporting public health interventions in diverse global contexts.