Five workshops were convened with about sixty technical experts to review alternative means of providing drinking water in the event of destruction, impairment, or contamination of the public water supply. Various scenarios were assumed, such as destruction or impairment of the water infrastructure by a powerful earthquake and contamination events requiring alternate supplies of drinking water. The term “emergency water supply” will be used instead of the equivalent terms “alternative water supply/sources” throughout this report. Based on the severity of an incident, all levels of government (local, state and federal), as well as non-governmental organizations (NGOs), like the Red Cross, may become involved.