When natural disasters Occur, the shortage of drinking water becomes a problem not only for the disaster victims, but also for the people involved in their rescue and safekeeping. A water purification unit has been designed, meeting specific criteria of efficiency, size, weight and power consumption. A hollow fiber ultrafiltration (UF) membrane module, with a 100 kDa cut off, has been chosen and integrated into a miniature pilot plant, transportable by plane and portable by four men. The power necessary for operating the pilot plant is 0.6 kW and can be provided by an electricity generator. In less than 30 min, the unit is ready for production. The maximum production reaches 1000 L h(-1), which can easily meet the demands of drinking water for the rescue team and disinfected water for medical care.