System 02 — Preparedness

The 72-Hour Readiness System: Three Days, Five Subsystems

Seventy-two hours is the window emergency managers plan around: the time for roads to clear, crews to restore power, and help to organize. This system covers a household of four for that window — water, food, power, light and information, warmth — with the math in the open, because "72-hour kit" is the most abused label in the industry.

Last updated November 4, 2026 · How we choose · The email version of this checklist is the printable one-pager offered below

The label problem, first

Many commercial "72-hour kits" for one person contain roughly 1,200–1,600 calories total. An adult needs about 2,000 calories a day. A kit can be honest gear and still be a one-day kit wearing a three-day name. So this system starts from the planning figures used by FEMA and the Red Cross — 1 gallon of water per person per day, ~2,000 calories per adult per day — and builds to the numbers, not the names. Four people, three days: 12 gallons of water and roughly 24,000 calories is the actual target. Everything below serves those two numbers plus power.

Subsystem 1 — Water (storage first, filtration behind it)

• 12 gallons stored — two 7-gallon rigid containers (the Aqua-Tainer class) or a case rotation of bottled water. Stored water is the only water that works during a boil notice at hour one.
• Filtration for the long tail — a squeeze filter for volume, a press-style purifier bottle for questionable sources. Filters turn the bathtub, the water heater, and the creek into reserves.
• The water heater reserve — know your home's water heater size and how to drain it safely. For most houses that's 40+ gallons of potable water already inside the walls.

Subsystem 2 — Food (pantry depth first, kits second)

• A deeper normal pantry — two extra weeks of the shelf-stable food your household already eats, rotated through normal cooking. Zero waste, zero weird meals, and it covers most real events by itself.
• Freeze-dried kits for the grab-and-go layer — for the tote that leaves with you. Read the label in calories per day, not servings per box.
• A way to heat water without power — a camp stove from the kitchen system or a simple alcohol burner; freeze-dried food without hot water is a sadder system.
• Comfort items count — coffee, tea, electrolytes, something sweet. Morale is a logistics input; planners who ignore it plan worse outcomes.

Subsystem 3 — Power (sized, not guessed)

The outage load for this system: fridge (~1,200 Wh/day), lights (~100), phones (~40), router (~240), one CPAP (~480 with humidifier, ~240 without). Total: roughly 1,800–2,100 Wh/day. Run your own household through the calculator — the prescription is a 2kWh-class station for a disciplined day, a 3.6kWh class for comfort, solar or a small generator behind either for day three. The station also serves the vehicle kit's logic when the truck becomes the plan.

Subsystem 4 — Light & information

• NOAA weather radio with battery backup — the Midland ER310 class: crank, solar, and USB charging, plus a USB-out to top a phone.
• A lantern per living space, a headlamp per adult — light is how a house stays calm and functional after dark.
• A paper card: numbers, addresses, meeting point — the plan that works with every battery dead.

Subsystem 5 — Warmth, shelter, and the human stuff

• Warmth without the furnace — one room, closed off, with the blankets and bags you already own, is the winter plan. (Never combustion heaters indoors without ventilation and a CO detector — that sentence saves more lives than any product on this page.)
• Medications: a 3-day buffer minimum — the subsystem nobody can buy at the last minute. Build the buffer with your pharmacist, one refill cycle at a time.
• Documents and cash — photos of documents on your phone, a sealed envelope of copies, small bills. Systems fail at paperwork more often than at gear.
• Pets are household members — their food and water go in the same math, same checklist.