Bottom line is 30 days! Katrina shows areas still under flood waters, well
after a week. The object is NOT rescue! I maintain 6 months food and water
in my food cellar.

How much space does 6 months worth of food and water occupy?

Less than 50 cubic feet, but not much less.
If you stored it under the bed,
the bed would have to be 32" high, plus the mattress.
It would also weigh in excess of one US statute ton,
so you might want to spread it around a bit.

(Reality check:
Dinty Moore Beef stew is 222 calories/cup,
so you need 10 cups/day. Since it comes in cans,
there's wasted space to the tune of an extra 25%
so the storage volume is 12.5 cups/day or
around 10 days/cubic foot, for food.
Counting the wasted space, water is around
7 gallons/cubic foot. with around, .4cuft
wasted space.
Figure 2000 calories/day, and 1 gallon of water.)
Use the space between cans and bottles for
vitamin supplements, other drugs, variety-food)

Each of your 1,800 cups of stew weighs
236 grams, or around 1/2 a pound,
call it 1,000 pounds of stew and can.
Each of your 180 gallons of water
weighs 8 1/3 pounds or 1500 pounds,
total.)

Note that you can probably get your food
volume/weight down if you work at it,
but most of the really lightweight/small
packaged foods depend on having a ready
supply of water to re-constitute.
Rumor has it that eating a dehydrated
ration without rehydrating it FIRST is really,
really bad. As in, may well kill you bad.

--Goedjn