Storage of water in water storage barrels is a matter of life and death during an emergency situation when municipal water supplies are interrupted. The barrels must be USDA-certified for water storage since certain plastics can leach chemicals into water over long-term storage. All water has a percentage of bacteria within it which may multiply over time, causing the water to become unfit for human consumption. Storage of water barrels requires a cool location as well as proper treatment of the water itself to prevent contamination.
Set each barrel on a wooden pallet in a cool, dark location where they are to be stored and sterilize each barrel in place by pouring boiling water--which has been at a hard boil for a minimum of 20 minutes--into the barrel, filling it half full. The water must have been boiled for at least 20 minutes. Add 1/4 cup of 35 percent strength food-grade hydrogen peroxide per gallon of this water. Place the lid on the top of the barrel to contain the steam and allow to sit for four to six hours.
Boil enough water to fill the remaining empty space in each barrel to within one inch from the top. Boil the water to a hard boil for a minimum of 20 minutes, just as you did with the first fill. Calculate the number of gallons of this second batch of water and add an additional 1/4 cup of 35 percent strength food-grade hydrogen peroxide per gallon.
Fill the remaining empty space of each barrel with the second batch of peroxide-treated boiling water.
Rinse each water barrel lid with full-strength, undiluted hydrogen peroxide to sanitize and then place the lids on the tops of the water barrels tightly. Allow the barrels to remain in their cool, dark resting places indefinitely.