<![CDATA[Diarrheal disease remains one of the leading public health threats among children under five, particularly in densely populated urban settings where access to clean and safe drinking water is limited. This study examines the relationship between household drinking water quality and the incidence of toddler diarrhea in densely populated areas of Manado City, Indonesia. Employing a cross-sectional design, data were collected from 500 households through structured surveys, laboratory-based water quality testing, and review of local health records. The findings reveal that households relying on untreated well water exhibit significantly higher microbial contamination, especially elevated Escherichia coli levels, compared to those using piped water. Socio-economic disparities and sanitation conditions further contribute to variations in health outcomes, with low-income households experiencing disproportionately higher diarrhea cases. Regression analysis demonstrates a strong association between poor household water quality and increased diarrhea incidence in toddlers. The study highlights the urgent need for improved water supply infrastructure, routine household water treatment practices such as boiling or filtration, and targeted public health education to mitigate waterborne disease transmission. Strengthening collaborative efforts between communities and local authorities is essential to ensure water safety and reduce preventable child morbidity in urban high-density environments.]]>
