FEMA's emergency-kit guidance says a household should have its own food, water and other supplies for at least 72 hours. It calls for one gallon of water per person per day and at least a three-day supply of nonperishable food. FEMA also recommends putting supplies in airtight plastic bags and keeping the kit in one or two easy-to-carry containers, such as plastic bins or a duffel bag.
That is useful advice, but apartment storage has a hard limit: water is heavy. A four-person household needs 12 gallons for the minimum three-day baseline. At roughly 8.34 pounds per gallon, that is about 100 pounds of water before counting bottles, food or any other supplies. Do not build one giant tote and call it portable.
The CDC recommends trying to store two weeks of water if possible. In a small apartment, begin with the complete 72-hour floor, then add a second clearly labeled module as space and budget allow. Readiness should improve in useful layers rather than depend on a perfect setup that never gets finished.