Three days without water is life threatening. So how much water does the average, healthy adult living in a temperate climate need? For men is roughly about 13 cups (3 liters) of water daily. And for women is about 9 cups (2.2 liters) a day.

Your water supply is the first thing to get ready whether you are staying at home through an emergence or having to evacuate.

You can purchase bottled water and store, I suggest  1 gallon or larger jugs because the small bottles are flimsy and hard to deal with. If you have city water you can bottle you own and save some money. The containers should be new or well cleaned. Fill them with safe, drinking water. All public water supplies are already treated and should be free of harmful bacteria. However, as an additional precaution, it is recommended that you add 5-7 drops, about 1/8 teaspoon, of chlorine bleach per gallon of water stored.
Here are many types of water containers.

In the case that you have to evacuate your home you’ll need to have a different plan for your water supply. Water is heavy over 8 lbs per gallon and you will need almost a gallon a day. The good news is there light weight filters that allow you to drink from  almost any water source safely and they come in different sizes depending on your needs.
Emergence water filters.