One essential, apart from weapons, which you will require to survive the zombie apocalypse, is water. Yes, if zombies don't kill you then probably thirst will. So, it is important to store about three day's water supply for every person. One gallon of water is sufficient for a single person per day. This one gallon per person excludes the water required for household chores such as washing clothes, doing the dishes or bathing. Also, take note of tricks you can use to clean and purify water such as boiling, distillation, filtering, adding iodine and chlorine treatments. Anyways, the water supply will come handy in case of any other calamity also, apart from zombie attacks.