A sensible order

There's no single right way to prepare, but there is a sensible order, because some things matter within days and others only within months:

  1. Water and food. You need water within days. FEMA says to drink at least half a gallon a day and store at least a gallon per person per day, and never to ration it: drink what you need today and find more tomorrow (FEMA).
  2. Power for the things that keep water and food going: a well pump, the fridge or freezer, heat, medical gear, a radio. That's what the guides size for you.
  3. Shelter that stays warm or cool without the grid: insulation, a heat source that doesn't need power, one room you can close off.

How far to go

Each step up covers far more of what actually happens:

  • Three days is the basic kit everyone should have (Ready.gov). It covers the everyday outage, which lasts hours.
  • Two weeks is the target FEMA and Washington State use. Washington's reason is plain: electricity, gas, water, sewage, internet and phones "may be cut off for many days, weeks or months," and help may take days or weeks to arrive (Washington EMD, FEMA). Two weeks covers Texas 2021, where outages lasted nearly four days (FERC/NERC), and most of Kentucky's 2009 ice storm, where much of Louisville was dark for 10 to 14 days (Kentucky Living).
  • A month covers the worst ice storms: in 1998, some homes in Quebec waited about a month (National Weather Service).
  • Three months covers Puerto Rico after Hurricane Maria, where the average home went 84 days without power and 68 without running water (NEJM).

Past about three months, storing more stops paying off. Stored water needs replacing every six months (FEMA), and three months for a family of four is about 360 gallons. Beyond that, the better buys are things that keep going on their own: power that refills itself from the sun, a water filter or well, food you rotate through and eat.

Keep it simple

  • Store what you eat, eat what you store. FEMA's advice is to build the food supply from the canned and dry food you already buy, oldest first (FEMA).
  • Date your water. Fill clean containers, write the date on them, keep them somewhere cool and dark, and replace them every six months (FEMA).
  • Then power. Start with your own setup or pick where you need power, and see how long it lasts in a long winter outage or a grid-down.