Emergency Water Supply Calculator
Enter the number of people and the days you want to cover.
Your numbers
FEMA advises at least several days; two weeks is a common home target
Increase for hot climates, nursing mothers and sick people
Your results
Water to store (US gallons)
Water to store (US gallons)
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In litres
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Containers needed
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Weight (kg)
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Emergency Water Supply Calculator by TheCalcTools
How the Emergency Water Supply Calculator works
Ready.gov (FEMA) recommends at least one gallon of water per person per day for drinking and sanitation. Children, nursing mothers, sick people and hot weather need more; pets need water too.
Store commercially bottled water or clean food-grade containers in a cool, dark place, and replace stored tap water every six months.
The formula
Gallons = people × days × gallons per day
Worked example
Using the default values shown in the calculator:
| People | 4 |
|---|---|
| Days to cover | 14 |
| Gallons per person per day | 1 |
| Bottle or jug size (litres) | 19 |
- 4 people for 14 days at 1 gallon a day: 56 gallons (212 litres).
- That fills 12 jugs of 19 litres.
Result:
| Water to store (US gallons) | 56 |
|---|---|
| In litres | 212 |
| Containers needed | 12 |
| Weight (kg) | 212 |
Frequently asked questions
How much water for a family of 4 for two weeks?
56 US gallons (212 litres) at one gallon per person per day.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.