"Clean, safe, drinking water is one of the top concerns when there is an emergency. The average person can only live approximately 3 days without water. I personally think I'd run into trouble before my three days were up. Drinking contaminated water can cause a variety of illnesses and even death. However, packing enough water for an evacuation can be bulky and heavy. Every two cups of water adds a pound to your pack. So a gallon is 8 pounds! Seriously, that gets heavy fast, especially if you're having to hike into your location or also have to supply water for youngsters too little to haul their own."