Emergency Water Needs Calculator
Determine exactly how much water each person in your group needs for 72 hours. Adjust for age, activity level, and climate to build a plan that actually works when taps run dry.
Tips for Building Your Water Plan
- Store water in food-grade containers and rotate every 6 months
- Include purification methods (filters, tablets, boiling) for backup
- Remember hygiene water—plan at least 1 gallon per person per day
- Factor in pets, cleaning, and medical needs for total volume
- Stagger storage between multiple containers to prevent single-point failure
Water Storage FAQs
How much emergency water should I store per person?
Plan on at least one gallon of potable water per person per day for drinking and basic food preparation. This calculator uses that benchmark and scales up when activity level or climate increases demand.
Why does activity level matter when estimating water?
Physical work, hiking, or hauling gear speeds up evaporation and sweat loss. Selecting a higher activity level adds 10–20 percent more water so you do not come up short during strenuous evacuations or recovery tasks.
Do I need extra water for cooking and hygiene?
Yes. Drinking water is the priority, but you should budget additional volume for washing hands, dishes, quick sponge baths, and rehydrating meals. Many preppers add at least one extra gallon per person per day for sanitation.
How often should I rotate stored water?
If you fill containers from the tap, refresh them every six months. Commercially bottled water usually lasts 1–2 years unopened. Inspect containers regularly and keep them out of sunlight to prevent algae growth.
What containers are safest for long-term storage?
Use BPA-free food-grade plastic barrels, purpose-built water bricks, or stainless-steel containers. Avoid milk jugs or any plastic that previously held sugary drinks, because residue can feed bacteria and cause leaks.