Convenient access to safe water is central to human health and development. Water-borne disease remains a major cause of mortality and morbidity in the world, much of which could be eliminated by a combination of better water, sanitation and hygiene (WaSH). The WHO estimates that around 502 000 deaths a year in low and middle income countries from diarrheal disease are attributable to unsafe water, and that over 1 000 children under 5 die each day from diarrheal disease caused by inadequate WASH. UNWomen estimates that in Sub-Saharan Africa alone, women and girls spend 40 billion hours a year collecting water, the time valued at around 0 billion a year. Sustainable development goal no. 6 'ensure availability and sustainable management of water and sanitation for all' creates a framework for tackling the challenge of mobilizing the large investments required and making WaSH available at affordable prices. The purpose of the study on which this report is based is to analyze, capture and synthesize lessons learned from closed GPOBA water projects in order to evaluate the impact of the subsidy schemes and inform the scale-up and replication of OBA approaches. These lessons offer insight to successes and failures of project design and implementation as well as solutions to more complex projects and/or less tested environments.