Topic Overview

Having a supply of food and water can be helpful in any kind of extended emergency, whether it is a national security emergency or a natural disaster. If you are unable to leave your home, if the local water supply becomes contaminated, or if access to food and water is limited or unavailable, emergency supplies may be able to sustain you and your family until the emergency has passed.

The question of how long you should plan for your supplies to last does not have an easy answer. It is impractical for most people to store and maintain large reserves of food and water, and it is unlikely that you will ever need them. Having a short-term supply, however, may make sense. Most public health organizations recommend that you have enough food and water to last from several days up to 2 weeks.

Water is the most important part of any emergency supplies kit. You can exist on very little food for a long time, but after a short time without adequate water, your body will not be able to function. Most people need about 2 L (2 qt) per day. Including the water needed for hygiene and cooking as well as drinking, a reasonable guideline is to store 4 L (1 gal) of water per person per day. So, a family of 4 who wanted to keep a 1-week supply of water on hand would need to store 112 litres (4 litres per day per person, times 4 people, times 7 days). A 3-day supply for 4 people would be 48 litres.

Remember that water and most food supplies—even some "non-perishable"—have to be replaced periodically.

  • Replace bottled water that has remained sealed and unopened once a year.
  • Replace water that you filled yourself or bottled water that has been opened every 6 months.
  • Visit the website of the Canadian Red Cross at for information on the best foods to store and how often to replace food supplies. Some may need to be replaced every few months, while others may remain safe to eat for much longer.

Related Information


    ByHealthwise Staff
    Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
    Brian D. O'Brien, MD - Internal Medicine
    Kathleen Romito, MD - Family Medicine
    Specialist Medical Reviewer Christine Hahn, MD - Epidemiology

    Current as ofNovember 20, 2015