This information was prepared by the Federal Emergency Management Agency's Family Protection Program, which provides information to help families prepare for all types of disasters. Stocking water reserves and learning how to purify contaminated water should be among your top priorities in preparing for an emergency. You should store at least a two-week supply of water for each member of your family. Everyone's needs will differ, depending upon age, physical condition, activity, diet and climate. A normally active person needs to drink at least two quarts of water each day.
Hot environments can double that amount.
Children, nursing mothers and ill people will need more. You will need additional water for food preparation and hygiene. Store a total of at least one gallon per person, per day. Drink the amount you need today, and try to find more for tomorrow. You can minimize the amount of water your body needs by reducing activity and staying cool.