In the event of a thermonuclear attack on the United States, it is assumed that a major proportion of existing hospital facitlties would be destroyed. In recognition of these facts, the U.S. Public Health Service has pre-positioned Packaged Disaster Hospitals (PDH's) in communities throughout the nation. The PDH is a unit of supplies and equipment which, in disaster, can be set up in an existing building, such as a school, to supply an austere but functional general hospital. The booklet is the sixth in a series developed to assist those persons in a community responsible for preparing to use the PDH in a disaster. It discusses water conservation techniques, suggests guidelines for meeting the emergency water requirements of the PDH (both quantity and quality), and contains sufficient information to be used as a training manual for familiarizing assigned operating personnel with their responsibilities and with actions required to activate the water supply section.