Oxfam Water Supply Scheme for Emergencies. This manual is part of a series of guides devised by the Oxfam Public Health Engineering Team to help provide a reliable water supply for populations affected by conflict or natural disaster. Wherever possible, water supplies in emergency conditions should be obtained from underground sources by exploitation of springs, tubewells, or dug wells. No filtration will then be needed. However, if sources are not available or cannot be developed, the use of surface water from streams, rivers, lakes or ponds becomes necessary. Usually these surface sources are polluted. The level of faecal contamination can be measured by use of the Oxfam/Delagua Water Test Kit (see Section C). Where a serious level of faecal pollution exists, it is essential firstly to try to reduce the cause of contamination, and secondly to treat the water to make it suitable for human consumption. The Filtration equipment provides a simple, long-term physical and biological treatment system that requires no chemicals (except small amounts of chlorine required during filter cleaning) and needs only simple regular maintenance