The Red Cross, FEMA, and other disaster relief agencies recommend storing a 3 day supply of water for everyone in your household. I am more comfortable with 2 weeks worth. They estimate 1 gallon per person per day. That is 2 quarts for drinking and 2 quarts for cooking and other limited use. A family of 4 needs 4 gallons a day or 28 gallons for a week. This may vary with the climate your in. If you are in a hot climate store a bit more and rotate it more often.

The safest way to store water is to buy gallon containers of bottled water and keep them unopened. There are great large drum containers and 3 to 5 gallon container available as well. You should always use clean food grade containers. 2 liter soda bottles are great. Avoid juice bottles and milk jugs as they have sugars and proteins that promote bacteria growth and are a health risk. Also gallon milk containers are made of a type of plastic that becomes brittle with age and may crack. Glass containers may break in an emergency and are heavy to carry.

Rinse bottles with dish soap and hot water. You can sanitize with a teaspoon of non scented liquid bleach. Bleach should also be in your storage as a disinfectant. Swish the solution around in the bottle then empty and rinse before filling. If you get your water from the tap and it is commercially treated with chlorine it is safe as it is. If water is from a well or source not treated, add two drops of non-scented liquid bleach. Fill the bottle to the top and seal tightly. If it may freeze where it is stored fill as full as you can and squeeze out some air leaving room for expansion.

You should rotate the water every 6 months. Simply empty them in the garden or lawn and refill. Store in a cool dark place. Avoid direct sunlight. It promotes growth of algae and bacteria. It may seam bothersome to store 30 or so gallons of water, but if you are not prepared in an emergency you will wish you had done so.