Having a supply of food and water can be helpful in any kind of extended emergency. 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, your family may be able to live on emergency supplies 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's impractical for most people to maintain large reserves of food and water, and it's unlikely that you will ever need them. Having a short-term supply, however, may make sense. The Red Cross recommends that you have enough food and water to last at least 3 days.

Water is the most important part of any emergency supplies kit. Without it, your body will not be able to function. Most people need to drink about 2 litres of water per day. Including the water needed for hygiene and cooking as well as drinking, a reasonable guideline is to store 4 litres of water per person per day. So, a family of 4 that 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 have to be replaced periodically.

• Replace bottled water that has remained sealed and unopened once a year.
• Replace water that you have opened or filled yourself every 6 months.
• Rotate and replace your food supply regularly. Check the expiration and "best by" dates on food items and use older items first. Some foods may need replacing every few months; others may remain safe to eat for much longer.