If there is power outage for a longer period of time, those living in apartment buildings at higher floors might also have problems with their water supply. During this situation, you need to have alternative sources to get your water.
Aside from foods you also need to store water. It is best to store water separately from your food. By doing this, you will have more flexibility in storage areas. You can store beans, grains and dried food in areas that might reach freezing temperatures like the attic or storage space. However, this might not be ideal for canned foods. Also, you can store water in areas that might attract rodents.
Also, in case you need to transfer, it will be easier for you to take your food and your water containers and move easily to a new area.