The Beans, Bullets, bandages, & You Blog has a great article on Dehydration. Staying hydrated during an emergency situation or disaster is very important. Therefore, having a ready supply of water is vital to surviving an emergency situation or disaster.
According to the American Prepper Network, the five main skills needed for a long-term disaster are abilities related to power, water, shelter, food, and basic survival skills. My take on this is very similar, except that I’ve replaced power generation experience with medical experience.