Trends, projections, and socioeconomic decomposition of improved water and sanitation access in Ethiopia

Access to improved water and sanitation (WaTSAN) is essential for public health and sustainable development. This study examines trends, determinants, and socio-economic inequalities in WaTSAN access in Ethiopia from 2005 to 2019, and provides projections for 2025–2030 to inform Sustainable Development Goal 6 (SDG 6). A cross-sectional study was conducted using Ethiopian Demographic and Health Survey (EDHS) data from 55,736 households, with a stratified two-stage cluster sampling Technique. Multivariate decomposition and Wagstaff analysis were used to examine socioeconomic disparities in WaTSAN access, accounting for income, education, and geographic variation. Future projections employed both linear and logistic growth models with sensitivity analyses to account for methodological uncertainty. The proportion of households using improved WaTSAN sources increased from 4.66% in 2005 to 16.62% in 2019. The decomposition results show that 57.75% of the overall increase in the proportion of households using improved WaTSAN sources was due to Endowment (differences in the compositional characteristics of respondents), while 42.25% was due to Coefficient (the effect of independent variables). The Wagstaff index revealed pronounced inequalities, favoring wealthier households (0.335 [95% CI 0.2898, 0.381]) and those headed by individuals with higher education (0.1387 [95% CI 0.1047, 0.1727]). Regional and rural–urban disparities remain significant, particularly among communities with limited media exposure. Projections indicate that improved water coverage may reach 69–73% by 2030, though with substantial uncertainty (95% CIs 20–126% for the linear model, 35–100% for the logistic model). While Ethiopia has made progress in expanding WaTSAN access, significant socioeconomic and geographic disparities persist. Targeted policies, poverty reduction strategies, and increased media exposure are crucial for achieving equitable access. Projections suggest accelerated interventions are needed to achieve SDG 6 targets by 2030. The considerable uncertainty in long-term forecasts highlights the need for frequent monitoring and adaptive policy responses.