This paper focuses primarily on water supply service delivery in post-emergency settings and is intended for those who regularly work in providing emergency water supply services, as well as those who are involved in protracted humanitarian emergencies. It is divided into four parts: Part 1 is an introduction to the work that has been undertaken by Oxfam and UNHCR. Part 2 looks in more detail at the concept of sustainability and sets out a number of factors that should be considered if better service delivery arrangements are to be achieved. Part 3 provides insight into humanitarian crises in six case studies. Part 4 highlights some gaps in current practice and reflects on areas to improve water supply service delivery.