Access to safe drinking water, sanitation and hygiene (WASH) is widely acknowledged to play a transformative role in reducing poverty and strengthening livelihoods. Although many countries achieved significant progress in extending access to these basic services over the lifetime of the Millennium Development Goals (MDGs), the targets were criticised for their modest ambition and scope. The drinking water target was met in 2010, but with major disparities in access between and within regions, countries and groups. The world fell well short of achieving the sanitation target, with similar concerns raised about services, or rather the lack of them, for the poorest and most vulnerable people. The commitment to ‘leave no one behind’ under the Sustainable Development Goals (SDGs), adopted in 2015, marked a new and much-needed commitment to universality. World leaders have agreed ambitious new global targets to achieve universal access to safe and affordable drinking water and adequate sanitation and hygiene by 2030. The aim is to redress the huge and persistent inequalities in access to services that affect people’s lives. However, this shift in focus has major implications for the ways in which the next generation of WASH policies and programmes are conceived, designed, financed and monitored. ODI convenes an expert panel to discuss these issues and point the way ahead, drawing on the latest research presented in a new book, Equality in Water and Sanitation Services.