Why storing more than two weeks of water stops working

The short answer

A year of water for a family of four is 1,460 gallons. That is twenty-seven 55 gallon drums weighing about six tons. No ordinary household stores that, and nobody should try.

The number nobody selling you a drum will do out loud

Four people, 365 days, one gallon each per day. One thousand four hundred and sixty gallons. Twenty-seven full drums, a little over twelve thousand pounds, and somewhere between sixty and seventy square feet of floor given over permanently to water. Written down it is obviously absurd, which is why year supply pages tend to quote food in pounds and go quiet about water. We would rather say it plainly: past about two weeks, storage is not the mechanism any more, and every extra container you buy is solving thirty days of a problem that has no end date.

You already have more water in the house than you think

A domestic water heater holds between thirty and eighty gallons, and that water is clean and drinkable. It has a drain valve at the bottom, and you open a hot tap somewhere in the house first to let air in or nothing comes out. Turn off the power or gas to it before you draw from it. Your pipes hold a few more gallons that will drain to the lowest tap, and each toilet cistern, as opposed to the bowl, holds a couple more that are fine for washing. For a family of four that is often two to four extra days sitting in the building already. Tankless heaters are the exception and hold essentially nothing.

The combination that actually covers an open ended problem

Two weeks stored, a filter rated for bacteria and protozoa, and a source you have physically walked to. The stored fortnight means you never have to touch anything questionable in the period when most outages end. The filter means the thirty-first day looks like the fifteenth. The source is the part people leave abstract, and it is the part that matters: know which river, pond, butt, pool or neighbour, know how far it is, and know what you are carrying it in. At 8.34 pounds a gallon, fetching five gallons is forty-two pounds on the way back.

Keep track of what you actually have.

Provision Planner counts the water already in your house against the target on this page, and tells you how many days you really cover.

See how many days you cover

The next questions, answered

How much water is a year supply for a family of 4?

One thousand four hundred and sixty gallons, which is twenty-seven 55 gallon drums and roughly six tons. It is not a realistic storage target for a household, and treating it as one is the main reason year supply planning stalls.

How much water is in a water heater?

Usually thirty to eighty gallons, and it is clean. Drain it from the valve at the bottom with a hot tap open elsewhere to let air in, and cut the power or gas to the heater first. Tankless units hold almost nothing.

What should I buy instead of more water containers?

A gravity filter rated for bacteria and protozoa, and the time to identify a water source near you that you could actually carry from. Together they cost less than a few drums and they do not run out on a fixed date.