This report from 2016 analyses humanitarian and development water, sanitation and hygiene (WASH) approaches in South Sudan, and considers how and why siloes have arisen between the two. To improve complementarity, it identifies a need for common principles for WASH in protracted crises. These common principles comprise a short set of pragmatic, mutually agreeable ways of working for all external agencies that support the delivery of WASH, whether they identify themselves as part of humanitarian or development communities.