Abstract
BACKGROUND: Access to safe drinking water remains a major challenge in sub-Saharan Africa, where reliance on unimproved water sources exposes millions to waterborne diseases and undermines progress toward Sustainable Development Goal 6 (SDG 6). Understanding spatial patterns and determinants of unimproved water use is essential for targeting WASH interventions. METHOD: We analyzed data from 500,845 households across 20,492 clusters in 34 sub-Saharan African countries using Demographic and Health Surveys (2012-2024). Data was processed using Microsoft Excel and STATA version 17. Prevalence estimates accounted for the DHS complex sampling design. Spatial analyses (Global Moran's I, Getis-Ord Gi*, SaTScan™, Anselin Local Moran's I) and Geographically Weighted Regression (GWR) were conducted to identify clusters and key predictors. RESULT: Overall, 58% (95% CI: 51%-65%) of households relied on unimproved drinking water sources. This indicates that approximately three in five households utilize unimproved water source. Significant spatial clustering was detected (Global Moran's I = 0.2415, p < 0.001), with major hotspots in Madagascar, Uganda, Rwanda, Mozambique, Malawi, Chad, Nigeria, Togo, Burkina Faso, Liberia, Sierra Leone, Mali, Ethiopia, parts of Angola, the Congo Republic, Zambia, and Zimbabwe. SaTScan™ identified 109 significant clusters, and Local Moran's I revealed mixed high- and low-risk zones. GWR (adjusted R² = 0.917) highlighted key predictors: rural residence, female-headed households, older household heads (50 + years), poverty, limited media exposure, lack of electricity, and poor water access. CONCLUSION: Unimproved water use remains widespread and spatially concentrated across sub-Saharan Africa. The determinants identified by GWR poverty, rural residence, limited infrastructure access, and low household media exposure highlight critical inequities driving this burden. Addressing these disparities requires localized, data-driven WASH planning that prioritizes hotspot regions, expands access to affordable improved water systems, strengthens electricity and media outreach infrastructure, and supports vulnerable households. Implementing these targeted and multi-sectoral strategies is essential for accelerating equitable progress toward SDG 6 and improving public health resilience across the region.