Emergency Water Preparedness
How Much Emergency Water Should You Store at Home?
Use the CDC baseline to estimate household emergency water, account for pets and health needs, and plan a realistic storage target.
Direct answer
CDC advises storing at least 1 gallon of water per person per day for at least 3 days for drinking, cooking, brushing teeth, and other essential uses, and recommends trying for a 2-week supply if possible. Treat that as a planning baseline, then add for pets, heat, illness, pregnancy, cooking, and hygiene needs.
Questions This Guide Answers
How much emergency water should I set aside per person?
CDC’s baseline is at least one U.S. gallon per person each day for at least three days, with a two-week reserve if possible. Increase that starting amount for pets, illness, pregnancy, hot weather and your household’s actual needs.
Full guidance: Official guidance and a usable household plan · Sources: CDC — Create and Store an Emergency Water Supply
How many gallons does a family of four need for an emergency?
At the CDC baseline, four people need 12 U.S. gallons for three days or 56 gallons for two weeks. Those totals cover people only; add water for pets and any extra household needs.
Full guidance: The quick calculation · Sources: CDC — Create and Store an Emergency Water Supply
Is water for pets included in the one-gallon-per-person estimate?
Water for pets is additional to the one-gallon-per-person daily baseline. Plan a separate pet allowance and increase the household reserve where heat or other needs raise consumption.
Full guidance: A practical example · Sources: CDC — Create and Store an Emergency Water Supply
Can water saved for flushing count toward my drinking-water reserve?
Do not count nonpotable flushing water toward the household drinking-water reserve. PHS recommends keeping the two supplies separate and not counting pool water, rain-barrel water or suspect well water as ready to drink.
Full guidance: A practical example · Sources: CDC — Create and Store an Emergency Water Supply
How can I build an emergency water supply a little at a time?
PHS recommends starting with three days of accessible safe drinking water, then adding capacity in stages toward a longer reserve. Choose containers you can manage safely and plan their placement and rotation before buying bulk storage.
Full guidance: Official guidance and a usable household plan · Sources: CDC — Create and Store an Emergency Water Supply
Build in stages
1 gallon per person per day is an acceptable emergency-water baseline. CDC recommends at least three days for drinking, cooking, brushing teeth and other uses, and encourages a two-week supply when possible. This is a useful, legitimate level of preparedness.
About 3 gallons per person per day is an optional Prepared Home Solutions stretch goal when space, weight, budget, structural/storage capacity, and household circumstances allow. It is not a CDC/FEMA minimum. It offers extra flexibility for drinking, cooking, basic hygiene, cleaning/sanitation and unexpected needs. Build in stages: acceptable emergency baseline → improved reserve → optional PHS stretch goal. Add for pets and household-specific needs.
How much water is in a case of bottled water?
A typical 24-pack of 16.9-fluid-ounce bottles contains 405.6 U.S. fluid ounces: 24 × 16.9 ÷ 128 = approximately 3.17 U.S. gallons, or about 3.2 gallons. Check the pack size and bottle label; cases vary.
Cases help visualize your supply, but add up quickly for several people over several days. Plan storage space, weight and manageable containers, along with a backup source beyond the water you store.
The quick calculation
People × days × 1 gallon gives the CDC baseline. For a family of four planning for three days, that is 4 × 3 × 1 = 12 gallons. A two-week baseline for the same household is 56 gallons before adjustments.
CDC says to consider more for pregnant people, people who are sick, pets, or hot climates. One gallon is a starting estimate, not a guarantee that it covers every household’s cooking, hygiene, or medical needs. Review your family’s actual use and any local emergency instructions.
A practical example
A two-adult, one-child household with one medium dog planning for seven days might start at 21 gallons for people, then add a separate allowance for the dog and for extra use in hot weather. Keep drinking water separate from water intended for cleaning or flushing. Do not count pool water, rain-barrel water, or untested or suspect well water as ready-to-drink supply.
Water weighs about 8.34 pounds per U.S. gallon. A 7-gallon container holds roughly 58 pounds of water plus the container. Two such containers hold 14 gallons and weigh about 117 pounds of water. Plan where they will sit and how they can be lifted safely.
Official guidance and a usable household plan
Official guidance: CDC — Create and Store an Emergency Water Supply sets at least 1 gallon per person per day for 3 days as the baseline, calls for more in some situations, and says to try for two weeks if possible.
PHS practical recommendation: Begin with three days of accessible drinking water, then build toward a longer supply in stages. Store some in manageable containers near the point of use and put heavier bulk containers low, on a floor that can support the load. Label the fill date and establish a calendar reminder for rotation.
What this estimate does not cover
It is not a full water-demand engineering calculation. A household relying on a well may lose pumping when electricity fails even if the well itself is intact. Infants, medical devices, special diets, larger pets, livestock, and prolonged hot weather change the requirement. Follow health-department advice during advisories or contamination events. For storage logistics, see choosing containers; for freshness, see how long stored water keeps.
Common mistakes
- Buying a large tank before calculating a realistic quantity and placement.
- Forgetting pets or counting nonpotable flushing water toward the drinking-water reserve.
- Assuming a filter can make chemically contaminated water safe.
- Putting large containers where they cannot be accessed safely.
Put your water plan on paper
Use the completed PHS Household Emergency Water Plan & Worksheet (PDF) to record your stored supply, source backups, equipment and next steps. Learn through the guides, answer specific questions, plan with the worksheet, then act on the gaps that matter to your household.
For the complete layered approach, read Emergency Water Preparedness: More Than Just Storing Water.
Related Guides
Primary sources
- CDC — Create and Store an Emergency Water Supply
- Ready.gov — Build a Kit
- USGS — Water Density (weight varies slightly with temperature; 8.34 lb/U.S. gallon is a rounded planning value).
Need help with storage constraints?
Ask PHS about storage constraints if space or access is difficult.