Impact of poverty reduction on access to water and sanitation in low- and lower-middle-income countries: country-specific Bayesian projections to 2030.

BACKGROUND In 2017, 785 million people globally lacked access to basic services of drinking water and 2 billion people lived without basic sanitation services. Most of these people live in low- and lower-middle-income countries in South Asia, South-East Asia, and Sub-Saharan Africa. To monitor the progress towards universal access to water and sanitation, this study aimed to predict the coverage of access to basic drinking water supply and sanitation (WSS) services as well as the reduction in the practice of open defecation by 2030, under two assumptions: following the current trends and accelerated poverty reduction. METHODS AND FINDINGS Households reporting access to basic WSS services and those practicing open defecation were extracted from 210 nationally representative Demographic Health Surveys and Multiple Cluster Indicator Surveys (1994-2016) from 51 countries. A Bayesian hierarchical mixed effect linear regression model was developed to predict the indicators in 2030 at national, urban-rural, and wealth specific levels. A Bayesian regression model with accelerated reduction in poverty by 2030 was applied to assess the impact of poverty reduction on these indicators. Out of 51 countries, only nine (Bangladesh, Bhutan, Ghana, India, Nepal, Pakistan, The Philippines, Togo, and Vietnam) were predicted to reach over 90% coverage in access to basic services of drinking water by 2030. However, none of the countries were projected to achieve equivalent coverage for access to basic sanitation services. By 2030, 21 countries were projected to achieve the target of less than 10% households practicing open defecation. Urban-rural and wealth derived disparities in access to basic WSS services, especially sanitation, were more pronounced in Sub-Saharan Africa than South Asia and South-East Asia. Access to basic sanitation services was projected to benefit more from poverty reduction than access to basic drinking water services. Households residing in rural settings were predicted to receive greater benefit from poverty reduction than urban populations in access to both basic WSS services. CONCLUSION Achieving poverty eradication targets may have a substantial positive impact on access to basic water supply and sanitation services. However, many low- and lower-middle-income countries will struggle to achieve the goal of universal access to basic services, especially in the sanitation sector.