A city's water supply system is one of the main lifelines vulnerable to natural hazards and artificial threats. It is also the main lifeline to provide clean and healthy water for the aftermath period and temporary shelters, victims, and remaining residents. During a crisis, the lack of an emergency water supply plan increases the casualties caused. This research aims to develop a supply plan for emergency water during a disaster by introducing a comprehensive risk assessment. The selected software to do this included Arc-GIS and Scenario Wizard to prepare emergencies and reduce the casualties of the natural disasters inflicted on Kermanshah City as a case study. To achieve this plan, three phases should be carried out. In the first phase, the vulnerability and destruction scenarios should be determined using Cross-Impact Balance analysis (CIB) based on the descriptors and their interactive variables. In the second phase, the risk zonation maps with the drinking water supply approach should be developed by using geographical data superposing different layers. In the third phase, three support and supply centre grades are introduced, and their distribution maps are developed, which is implemented for Kermanshah City. Earthquake is considered as the main disruption event.