How Much Water Does a Family of Four Really Need? FEMA's Answer Is 28 Gallons a Week
By Marc Coleman · July 18, 2026
Ask a prepared family how much food they have and they'll point proudly at a wall of buckets. Ask how much water they have and there's usually a pause — then a guess. It's the blind spot inside the blind spot: you can live weeks without food, but only about three days without water.
The FEMA formula
FEMA's guidance is simple: store one gallon per person per day — half for drinking, half for cooking and basic sanitation. For a family of four, that's 4 gallons a day, 28 gallons a week, and 56 gallons for the recommended two-week reserve.
Most households, when they actually add up the bottles in the pantry, find they're holding two to three days of water. A single flat of bottled water — the thing that feels responsible to buy — is about three-quarters of one day for a family of four.
The cheap way to 14 days
- Bottled water cases (~3.2 gal each) — convenient, rotate through daily use.
- 5-gallon stackable containers — the workhorse; six of them is nearly an 8-day supply for four people.
- A 55-gallon barrel — one purchase that covers a family of four for almost two weeks by itself.
- Date everything and rotate every 6–12 months — stored water doesn't spoil like food, but it does go stale and pick up container taste.
The mistake to avoid
Don't count on “I'll fill the bathtub when something happens.” Warnings rarely arrive before the pressure drops, and an unlined tub holds unsanitized water you can't confidently drink. Storage you already own beats storage you plan to improvise.
Track it like you track food
The reason water gets ignored isn't laziness — it's that nobody measures it. Give your household one number for water the way you'd give it one number for food: how many days your supply covers the people under your roof. When the number is visible, it gets fixed.