An ample supply of clean water is a top priority during an emergency. As a general rule, store two or more gallons of water per person, per day in thoroughly washed containers. Do not use containers that have held toxic substances. Rotate stored water every six months.
After a disaster you should assume all water sources, other than commercial bottled water, are unsafe. Until you are notified that your public supply is safe to drink, there are two ways to purify water. Bring water to a rolling boil for three to five minutes. Let it cool and add oxygen by pouring back and forth between two containers. For an alternative method, add 16 drops of regular, unscented household bleach without additives to one gallon of water and let stand for 30 minutes. if there is no slight odor of bleach, repeat the procedure.