Water storage calculator
How much water your household actually needs, how many containers that is, and what it will weigh once it is full.
1. Household
Your numbers
- Total water needed
- 126 gal
- Containers
- 18 × 7 gal
- Drinking & cooking
- 56 gal
- Sanitation
- 56 gal
- Full weight
- 1,051 lb
- Floor space (approx.)
- 4.4 sq ft
Rounding up to whole containers gives you 14 days of supply at this consumption rate.
To disinfect clear water, use 6 drops of unscented 8.25% household bleach per gallon, stir, and let it stand 30 minutes. If the water is cloudy, let it settle and filter it through a clean cloth, paper towel, or coffee filter first, and double the amount of bleach if the water is cloudy, colored, or very cold. If your bleach is 6%, or you are treating a different volume, use the full EPA table. Planning guidance only.
Get the water storage worksheet
The numbers above are yours to keep — print them any time. The worksheet adds the fill-in planning sheet, the shopping checklist and the maintenance schedule.
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Questions people ask
- Is one gallon of water per person per day really enough?
- Ready.gov's figure is one gallon of water per person per day, for drinking and sanitation. It is a floor rather than a comfortable allowance, and the stated scope is optimistic: one flush of a conventional toilet uses more than the whole daily allowance. Sanitation is a separate line in this calculator for exactly that reason, because treating it as included is how people end up rationing drinking water to stay clean. In hot weather, or if anyone in the household is pregnant, ill or nursing, raise the drinking figure.
- How long does stored water keep?
- Commercially sealed bottled water carries a best-by date but stays safe well beyond it if stored cool and dark. Water you bottle yourself should be rotated every six to twelve months. Store off concrete, out of sunlight, and away from petrol, solvents or pesticides — some plastics let vapours through.
- What about the weight?
- Water weighs 8.34 pounds per gallon, so storage adds up fast. A 55 gallon drum is over 450 pounds when full and cannot be moved once filled. Check that any upper floor or shelf can carry the figure this calculator gives you before you commit to a location.