Food & cooking · Emergency preparedness
Emergency water storage calculator.
Enter your household and how many days to cover, and get the litres, US gallons, weight and number of jugs to store.
Inputs
Water to store
Enter the numbers above.
How much water to store for an emergency
Health Canada says to keep 2 litres of water per person per day to drink, and also suggests thinking about 2 more litres per person per day for cooking and cleaning. Public Safety Canada's emergency kits video gives about four litres per person per day in all. Ready.gov says one US gallon (3.79 litres) per person per day, for drinking and sanitation. Public Safety Canada and Health Canada say to be ready for at least 72 hours (3 days); Ready.gov says "several days". Multiply people by days by litres per day.
Worked example. A household of 4 for 3 days at the 4 L total: 4 x 3 x 4 = 48 litres, which is 12.7 US gallons, or twelve 4 L jugs. At the Ready.gov one gallon per person per day: 4 x 3 x 1 = 12 gallons, which is 45.4 litres. The "very hot weather" box doubles the daily amount, because Ready.gov notes that in very hot temperatures water needs can double.
Water weighs about 1 kg per litre, so 48 litres is about 48 kg before the containers. Spread it across several containers you can lift rather than one large drum.
Frequently asked questions
How much water per person per day for an emergency?
Health Canada recommends 2 litres per person per day for drinking, and also suggests thinking about 2 more litres for cooking and cleaning; Public Safety Canada gives about four litres per person per day in all. Ready.gov recommends one US gallon (3.79 litres) per person per day for drinking and sanitation.
How many days of water should I store?
Health Canada and Public Safety Canada say to be ready to take care of your household for at least 72 hours. Ready.gov says "several days". Store more if you can; this tool lets you enter any number of days.
Do pets need extra water?
Health Canada says to increase the amount of water on hand to include enough for your pets. It does not publish a per-pet figure, so use your vet’s guidance and add it to the total.
How long can stored water be kept?
Ready.gov says to keep commercially bottled water in its sealed original container in a cool, dark place, and to replace water that was not commercially bottled every six months.
Should I ration water in an emergency?
Ready.gov says never to ration drinking water unless authorities order it: drink the amount you need today and find more for tomorrow.
Sources
Checked
- Health Canada, "Food and drinking water safety in an emergency" (page dated 8 May 2026), opened 8 October 2026. 2 L to drink, 2 L more listed under items to think about adding for cooking and cleaning, 72 hours, pets, replacing supplies
- Public Safety Canada, Get Prepared, "Emergency kits", opened 8 October 2026. at least 72 hours; the page video states about four litres per person per day
- Ready.gov, "Water", opened 8 October 2026. one gallon per person per day, water needs can double in very hot temperatures, replace non-commercial water every six months
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Scope
Individual needs vary with age, health, activity and climate; children, nursing mothers and sick people may need more. This is a planning aid, not medical advice. Treat water of uncertain quality before drinking, following your local authorities.