Quick answer: enter your household size and planning period below. The calculator starts with one US gallon (3.8 litres) per person per day for drinking and sanitation, then adds the pet allowance and margin you choose.
6 US gallons (22.7 litres)
Plan basis: 2 adults, 0 children, 3 days, no pet-water allowance, no extra margin.
- Approximate stored-water weight: 50 lb (23 kg), before container weight.
- Equivalent to 6 one-gallon jugs or 2 five-gallon containers.
This is the baseline drinking-and-sanitation amount, not a prediction of exactly what your household will use.
What the total means
This is a planning floor, not a rationing instruction. The Centers for Disease Control and Prevention advises storing at least one gallon of water per person per day for three days and, if possible, a two-week supply. It also advises storing more for pregnant people, people who are sick, pets, and hot climates. Your household may need more for medical equipment, cooking, hygiene, or strenuous work.
The calculator treats adults and children equally because the published emergency-storage baseline is per person. Enter a separate daily pet amount based on what your animals normally drink or on advice from your veterinarian. The margin control is a simple planning buffer; it is not a medical calculation.
Build the supply without creating a new hazard
- Start with three days. If space and budget permit, extend the same calculation toward 14 days.
- Spread the weight. Water weighs about 8.34 pounds per US gallon before the container is counted. Several smaller containers are often easier to move and safer to store than one very large vessel.
- Use food-grade containers. Do not reuse containers that held toxic chemicals. Keep stored water away from fuel, pesticides, and direct sunlight.
- Label and inspect it. Write the fill date on each container and check for leaks, damage, contamination, or expired commercially bottled water.
- Keep treatment separate from storage. A filter or disinfectant may be a useful backup, but its effectiveness depends on the contaminant and the manufacturer’s limits.
Continue the water plan
- Use the emergency water hub for storage, treatment, advisories, and backup sources.
- Compare survival water filters by the job they can and cannot do.
- Plan for water after an urban disruption.
Sources and assumptions
The baseline and special-needs guidance come from the CDC emergency water supply guidance. The three-day starting point is also consistent with Ready.gov’s emergency kit guidance and the American Red Cross survival kit list. The conversion uses 3.785411784 litres per US gallon and an approximate room-temperature weight of 8.34 pounds per gallon.
Reviewed by Sean, the Secretive Survivalist, September 2026. This calculator is general preparedness information, not medical advice.