Water is probably the most important element of any survival kit, and the hardest to store. After a storm, you might not have a drop of water to drink. Your regular source of drinking water could be compromised because of contamination. There might not be any electricity to run your well's water pump. When the water isn't flowing, there's nothing to drink, nothing to bathe in and nothing to flush toilets.
The Federal Emergency Management Agency (FEMA) recommends storing at least 1 gallon (3.8 liters) of water per person per day for drinking and sanitation purposes. Children and nursing mothers might need more. If you live where it's warm, have additional water on hand. Bottled water in it's original container is best, and don't open it unless you're going to use it. Make sure you put the bottles in a cool, dark place [source: FEMA].
Be careful when storing your own tap water. Make sure the containers you use are specifically designed to hold water. You can buy these containers at a camping supply store. Wash each container with dishwashing soap and rinse well before filling them up. If you're going to use 2-liter plastic soda bottles, make sure you disinfect the bottles with a teaspoon of non-scented chlorine bleach mixed with a quart of water. Rinse the bottles out well. Close the top tightly with the bottle's original cap [source: FEMA].