Background: Ensuring access to improved water and sanitation remains a public health challenge in Ethiopia. Only 13 percent of Ethiopians used safely managed drinking water services in 2016. Exploring geographic variation and inequalities in access to improved drinking-water supply and sanitation will help track progress towards to meet sustainable development goals of water and sanitation by identifying risk populations for water borne diseases.

Objective: This study aims are to explore geographical variation and inequality in access to improved drinking water and sanitation in Ethiopia.

Methods: A total of 16, 650 households from 643 enumeration areas of the recent Ethiopian Demographic and Health Survey 2016 data were included in the analysis. World Health Organization recommended definitions were used to measure the indicator of basic services of improved drinking water and sanitation at enumeration area. Satscan spatial analysis was done using cluster of enumeration areas as center for exploring geographical variation of improved water and sanitation. Absolute and relative inequalities were used to quantify subnational regional inequality in access to improved drinking water and sanitation.

Results: Access to improved drinking water (considering fetching time within 30-minutes round trip of their household) and sanitation in Ethiopia was 49.6% (95% CI: 48.4-50.7) and 6.3% (5.8-6.8), respectively, with large variations between and within regions. Access to improved drinking water ranged from 28.5% in Somali region to 95.3% in Addis Ababa and access to improved sanitation ranged from 1.7% in Amhara Region to 24% in Dire Dawa. Most likely significant cluster in lack of access to improved water and sanitation was identified in northwestern parts (Amhara Region) and southern parts (South Nation and Nationalities and People Region) of Ethiopia. Most enumeration areas reported very low levels of access to improved drinking water and/or sanitation.

Conclusions: There are geographical variation and inequalities in access to improved drinking water and sanitation in Ethiopia. Monitoring geographical variation and inequality using spatial analysis and inequality indicators serves to identify underserved population which is useful for developing approaches to improve inequalities that can help a progress to achieve the 2030 Agenda for Sustainable Development.