Water

Water is the most important thing you should have in a zombie outbreak. Without water, or a source of water nearby, death is inevitable. Dehydration is deadly, and symptoms can manifest in a matter of hours, starting with an intensifying thirst and building to fatigue, chills, and headaches. Nausea will soon set in, and your muscles will cramp as your limbs start to tingle. The next set of symptoms includes vomiting, racing pulse, vision problems, confusion, seizures, and unconsciousness, which will all eventually lead to death. Stock up on water before the zombie outbreak, and always be on the lookout for the next source of drinkable water.