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Family Water Security Calculator

How much emergency water does your family actually need?

You do not need to predict the end of the world to prepare for the next boil-water notice, storm outage, frozen pipe, or week when stores are picked over. Start with the one thing every household needs first: water.

Vintage Defeat History fedora mascot beside stored water containers, a dripping faucet, and a family water checklist in a sepia field-guide scene.
Start with water. The calculator turns one vague worry into a clear household number.

Calculate your household water gap

Official guidance commonly starts at 1 gallon per person per day. This tool turns that into a family number and adds pets, formula/medical needs, and a small cleanup buffer.

This is planning math, not fear math. Start with one realistic step you can actually store.

Your family water target

Minimum drinking/sanitation water
35 gallons

For 4 people over 7 days, plus pets/extra needs.

7 cases of 24 half-liter bottles

Approximation only. Bottled water is easy to start with, but bulky.

7 five-gallon containers

Often easier to store under beds, in closets, or along garage walls.

Printable next stepSpouse-friendlyApartment-aware

Next: get the First 72 Hours guide

What to do after you calculate it

  • Store a realistic first layer this week, even if it is only one shelf, closet, or under-bed container.
  • Keep at least some water in grab-and-go containers in case sheltering stops being the safe option.
  • Print the First 72 Hours guide so your plan does not depend on power, Wi-Fi, or a charged phone.

Get the free First 72 Hours guide

Return to the Preparedness Meter

Next: connect the three core tools

Water, food, and readiness work best together. Check the other gaps while the numbers are fresh.

After you calculate your number

Once you know your household gallons, use the normal-family water storage buyer guide to choose boring containers that fit your home. If you want the printable labels, rotation checklist, water-notice action card, and spouse-safe planning script, see the Water Readiness Mini-Bundle.