In emergencies, surface water Sources are often used by relief agencies to provide raw water for treatment and subsequent Supply to internally displaced people (IDPs) or refugees. It has always proved difficult to obtain objective information on the reliability of proprietary emergency water treatment systems, or their limitations when actually in use during a crisis. The Centre for Environmental Health Engineering (CEHE) has been actively involved with Oxfam and other agencies for over 30 years and has been involved both designing and testing water treatment systems. The requirements of Oxfam and the other relief agencies have largely been refined over the last decade, in the light of hard won experience from a stream of emergencies. A selection of performance and operational issues relating to the Oxfam clarifier, pressure filters, precoat filters, membrane filters, ceramic filters and sachet water treatment products are described in broad terms.