Water Storage Calculator
How many gallons should your household store? Put in people and days, then add pets, a hot climate or extra hygiene water if they apply. Everything is worked out on your device. Nothing you type is saved or sent.
Your planning numbers
- Total to store for 14 days
- 56 gallons
- Per day, whole household
- 4 gallons
- Containers (5-gallon)
- 12
| People, 1 gallon a day | 56 gal |
|---|
Store water you have sealed in food-grade containers, in a cool, dark place. Water you filled yourself should be replaced every six months.1,2 The ASPCA says to keep at least seven days of bottled water for each person and pet, and to replace it every two months.4 A planning estimate, not medical advice. Needs differ with age, activity, pregnancy and health, so ask your clinician about yours.
Next steps
- Emergency water guide: how to store it and make it safe
- Water filter chooser and boil-advisory card (free printable)
- 30-day food storage calculator
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- WaterBOB bathtub water storage (paid link). Not a filter. A liner you fill in the bathtub before a storm, holding up to 100 gallons; the maker says it keeps water fresh for up to 16 weeks. You fill it when you have warning, before the storm.
- Waterdrop King Tank (paid link). A 2.25-gallon stainless gravity filter that needs no power. Downside: its carbon filters do not cover viruses, bacteria or parasites, so boil or disinfect questionable water first.
Where the numbers come from
- People: 1 gallon per person per day. Ready.gov and the CDC both give one gallon per person per day. Ready.gov says that gallon is for drinking and sanitation, so basic sanitation is already counted.1,2
- Hot climate: doubled. Ready.gov: in very hot temperatures, water needs can double. The box doubles the people figure only.1
- Pets: 1 ounce per pound per day (working estimate). PetMD gives about 1 ounce per pound of body weight per day for dogs. We could not find a veterinary per-pound figure for cats, so the same rate is used for every pet as a working estimate. The CDC says to store more water if you have pets.3,4,2
- Extra for hygiene: 1/2 gallon per person per day (our planning assumption). This one is ours, not a government or university figure. We found no published number for it. It is optional, and it sits on top of the one-gallon baseline that already includes basic sanitation.
Sources
Each link goes to the exact page cited. Pages opened and checked October 11, 2026.
- Ready.gov (FEMA). Water. At least one gallon of water per person per day for several days, for drinking and sanitation; children, nursing mothers and sick people may need more; in very hot temperatures water needs can double; water not commercially bottled should be replaced every six months. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. How to Create an Emergency Water Supply. At least 1 gallon per person per day for 3 days, a 2-week supply if possible, and more for pregnant women, sick people, pets or a hot climate; replace home-filled water every 6 months; use food-grade containers. Accessed October 11, 2026.
- PetMD (reviewed by Jennifer Larsen, DVM, PhD). How Much Water Should a Dog Drink?. Dogs should drink approximately 1 ounce of water per pound of body weight each day; individual dogs vary. Accessed October 11, 2026.
- ASPCA. Disaster Preparedness. At least seven days' worth of bottled water for each person and pet, stored cool and dry and replaced every two months. Accessed October 11, 2026.