Unequal water quality under decentralization: A case study of rural barangays in Antique, Philippines

Ensuring access to safe drinking water remains a major challenge in many low- and middle-income countries, especially in decentralized rural settings. This study examined water quality variations across four remote barangays in Barbaza, Antique, Philippines, and investigated contributing geographic and demographic factors. A total of 232 tap, drinking, and well water samples were analyzed for temperature, pH, total dissolved solids (TDS), electrical conductivity (EC), and the presence of Escherichia coli and coliform. Significant differences in EC and TDS (p < 0.01) were observed, with Binangbang Centro, a barangay relying primarily on groundwater, showing the highest median values. E. coli was detected in 23.1% of well water samples, while coliform exceeded standards (<1 colony/100 mL) in up to 100% of tap and drinking water samples. Despite widespread reliance on refilling stations, over 70% of drinking water samples contained coliform, possibly associated with post-purchase handling and storage conditions. Gua, the most densely populated barangay, recorded the highest coliform levels in drinking water (median: 102 CFU/mL). The findings highlight the need for barangay-specific strategies combining infrastructure improvements, decentralized monitoring, and hygiene education. This study supports context-sensitive policies to enhance rural water safety and community resilience under decentralized governance.