This study aims to estimate, on a global, regional and national costs and benefits of interventions that carry water and sanitation needed to achieve the MDG targets by 2015 and to achieve universal access. The report updates previous economic analysis conducted by the World Health Organization (WHO) coverage ratios using new water supply and sanitation services costs, income levels and health indicators. The study estimates the cost-benefit ratio and cost needed to achieve the MDG target on water and sanitation and achieve universal access to basic services. Rural and urban areas are analyzed separately.