<![CDATA[Background: Diarrheal diseases remain a major public health problem worldwide, contributing significantly to morbidity and mortality. One of the major contributing factors to diarrhea is exposure to contaminated water. The presence of coliform bacteria is used as a primary indicator of water quality. Therefore, detecting coliform is essential for assessing water safety and guiding sanitation measures. Purpose: This study aims to analyze the spatial distribution of coliform-contaminated water sources and assess the epidemiological risks of diarrhea caused by them, using a Geographic Information System (GIS) approach in the City of Surabaya in 2023. Methods: This study employed a quantitative approach using 693 secondary water source data points and diarrhea prevalence data in Surabaya. The analysis includes descriptive spatial analysis and spatial statistics to assess the distribution of coliforms and their epidemiological risk for diarrhea. Results: Clean water was the most contaminated with coliforms (43%), concentrated in Simokerto, Kenjeran, and Mulyorejo. Spatial analysis showed that high coliform percentages were associated with higher diarrhea prevalence, but Moran’s I indicated weak yet significant spatial autocorrelation (I=0.156; p=0.04). LISA and Bivariate LISA identified a Low-High (p<0.001) cluster in the northeast. Conclusion: The spatial distribution of coliform-contaminated water sources in Surabaya is concentrated in the central and northeastern regions, which are also characterized by a high prevalence of diarrhea. Therefore, continuous water quality monitoring and spatially targeted risk assessment are essential to support effective preventive public health interventions.]]>
