How Much Water Should You Store? A Simple Household Calculator

The most widely cited baseline, from FEMA's Ready.gov and the CDC, is at least one gallon of water per person per day, roughly half for drinking and half for food prep and basic hygiene. Ready.gov recommends a minimum of a 3-day supply for evacuation and, if you can, a 2-week supply at home.

Quick math

Adjust upward if…

• You live in a hot climate or are very active.
• Someone is pregnant, nursing, elderly, or ill (needs can be higher; ask a clinician).
• You have pets: plan for their water too (roughly an ounce per pound of body weight per day for dogs and cats is a common rule of thumb; check with your vet).
• You need water for medical devices or infant formula.

Start small

You don't need 56 gallons this weekend. Buy one case of sealed bottled water per trip, then add a couple of food-grade containers. Mark your calendar for rotation (see our storage guide).

Sources: Ready.gov (Water), CDC (Emergency water supply; making water safe). Last reviewed Oct 2026.