How Much Water Do I Need?

"You should have at least a three-day supply of water and you should store at least one gallon of water per person per day. A normally active person needs at least one-half gallon of water daily just for drinking.

Additionally, in determining adequate quantities, take the following into account:

• Individual needs vary, depending on age, physical condition, activity, diet, and climate.
• Children, nursing mothers, and ill people need more water.
• Very hot temperatures can double the amount of water needed.
• A medical emergency might require additional water."

(Source: http://www.fema.gov/plan/prepare/water.shtm)