Emergency officials estimate that you should plan on being self sufficient for the first 72 hours following a major disaster. But, in reality, it may take your community weeks or months to get back to normal. Therefore, it is highly recommended that you store at least a two week supply of water for each member of your family. Since everyone's needs differ depending on age, physical condition, activity, diet and climate, the amount of water you will need to store may vary from official recommendations. A normally active individual needs to drink at least two quarts of water each day.
Hot environments can double that amount.
Children, nursing mothers and those ill of health will require more. You will also need additional water for food preparation and hygiene purposes. As a general rule store a total of one to three gallons of water per person, per day. Store it in a cool, dark place. Calendar a date six months from now to refresh your water supply.