If a disaster that might disrupt local public water supplies seems imminent, it is prudent to store extra water to get through the situation. Large jugs of bottled water are effective but can be difficult to find once word of the disaster gets out. While your water is still running you can create a temporary water storage tank using plastic garbage bags and cardboard boxes. P
Instructables user yoav_liberman shares this method for building a 2-5 gallon tank: Cut an upside-down triangle on one side of a cardboard box. Insert the garbage bag into the box and carefully pull one of the corners through the triangle cutout and then twist the corner and pull into the point of the triangle. Fill the bag with water and tie the bag shut. The box protects the water filled bag from punctures.P
When you need to use the water cut the end off the corner you pulled through the triangle in the box; you can stop the water by twisting the corner shut and tucking it back into the point of the triangle.P
If you do this you’ll definitely want to use food-safe plastics, as some manufacturers lace garbage bags with pesticide to keep bugs out of the trash. Even so, I’d be more inclined to use this water for washing and flushing the toilet rather than consuming. If you know a water outage is on the way make sure to fill all your bathtubs and any other empty containers as well.
Article Source: http://lifehacker.com/5838990/diy-emergency-water-storage-tank