How global targets on drinking water were developed and achieved

Millennium Development Goals (MDGs) have passed their target year of 2015 and are followed by Sustainable Development Goals (SDGs). One of the MDG targets was halving the population without sustainable access to safe drinking water. It was the first target achieved in the long history of internationally agreed global targets on drinking water. However, a simplified monitoring indicator could have led to the mistaken conclusion that the MDG target on 'safe' drinking water had actually been achieved. We show that the major contributors to the achievement of the MDG target were China and India and that the increase in the percentage of population with access to improved sources was closely associated with economic development in most nations during 1990-2015. We expect that a synergetic relationship between drinking water access and economic development will be consistently true for most nations in the current SDG Target 6.1, which aims to secure safe and affordable drinking water for all.