The Centers for Disease Control recommends that you store enough emergency drinking water in your household to last two weeks. It estimates that you'll need a gallon of water per day for each person and pet in your household. If you are unwilling or unable to meet the recommendation, the CDC stresses that you should have at least three days' worth of water on hand. You'll need more if your local climate is hot or if any one is ill or pregnant in your household.
Cleaning the Containers
Although commercially bottled water is the safest and most convenient solution for storing emergency drinking water, it is also expensive; it also needs to be replaced every six months so that it doesn't taste like plastic. You can store your own water using food-grade containers, as long as they can be tightly sealed and are not easily breakable. Before use, clean the containers once, using dish-washing detergent and twice, using a solution of one teaspoon unscented household bleach to one quart of water. Let the containers air dry after the solution is poured out or rinse the containers using the clean water that you intend to store as emergency drinking water.
Disinfecting the Water
You can boil or filter the water, or you can use disinfectants to your emergency drinking water. Although some filters can catch some disease-causing protozoa and even bacteria, this is not true of all filters. As such, you should use the filters to remove minerals before either boiling the water or adding disinfectants. Bringing the water to boil for three minutes should be enough to make it safe. Alternatively, you can add 1/8 teaspoon of bleach in each gallon before stirring to disinfect the water.
Storing the Water
Label the storage containers with their storage dates so that you'll know to replace them every six months. Keep the containers stored under cold, dark, but dry conditions because heat and light can cause damage to plastic. Similarly, keep the containers away from gasoline, pesticides, and similar chemicals because their vapors can penetrate the plastic. Freezers are excellent places to store your emergency drinking water provided that they are not made of glass because glass can crack under the pressure of expanding ice.