Emergency managers still teach one gallon per person per day for drinking and basic hygiene, more in heat or for medical needs. A family of four that wants ten days is looking at forty gallons before cooking and washing. That is weight, space, and rotation, not a slogan.

The gallon is a floor for drinking and basic hygiene, not a shower budget. Hygiene is on the list because small problems get larger when washing stops. Heat and medical needs push the floor up. Cooking and washing sit above it. A family of four aiming at ten days is already looking at forty gallons before those extras. That is a closet problem: weight, space, and a rotation you will actually keep.

Stored water runs out. The second system is treatment: a gravity filter you have actually used, unscented bleach at a known dose, or boiling if you still have fuel. A filter in the wrapper is a donation to your future panic.

Water does not get smaller because the plan sounds tidy. Stored jugs have to be liftable by the people who will be home, including when an elevator is not a plan. Rotation means those jugs are drunk in ordinary weeks and refilled, so the emergency supply is not a surprise you meet years later. A number on a webpage is not water until the containers are in the house.

Know the water that is already on the property — the hot-water tank, the toilet tanks (not the bowl), a rain barrel you trust only after treatment. Label what is drinkable. In the dark, labels matter.

A known bleach dose is the dose you took from a health authority while you could still read it carefully, then wrote on the bottle and on the one-page plan. It is not a figure recalled from a thread in the dark. Boiling is real only if the fuel and the pot are real, and only if the steam is not filling a closed room. A gravity filter you have never wet is a sealed promise.

The hot-water tank is a finite tank, useful only if you can shut it down and take water without flooding the house. Toilet tanks mean the upper tank, not the bowl. A rain barrel is untreated water no matter how clear it looks. Labels made in daylight — drinkable, treat first, do not drink — are the instructions that still work when you cannot see the container you grabbed.