There is growing acceptance that the progress delivered under the Millennium Development Goal target for drinking water and sanitation has been inequitable. As a result, the progressive reduction of inequalities is now an explicit focus of the Sustainable Development Goal (SDG) targets, adopted in 2015, for universal access to drinking water, sanitation and hygiene (WASH). This shift in focus has implications for the way in which the next generation of WASH policies and programmes will be conceived, designed, financed and monitored.