Other Survival Needs
Always carry water with you. If you are lost and in a survival situation, you need to find water within two to three days. But take note that most water today carries the risk of some type of contamination, either from rain or runoff from livestock or crop fields. That is why it's important to ensure the water you drink is purified first. Two major risks are the giardia and cryptosporidium parasites - ingesting either of these can make you very sick.
Water purification tablets are available, but some people are sensitive to the chemicals.
Small portable water purifiers work well and can be carried in a pack. This technology has become so advanced that the portable water purifier will remove 99.9% of waterborne contaminates.
Boiling water is the safest method of purifying water. Bring the water at a rolling boil, let it cool before you drink it, and then start boiling some more.
Most individuals can go without food for two to three weeks. Packing some high-energy power bars or trail mix in your pack for emergency situations is a good idea. If you have harvested game, start a fire. You will eat well! But it is not a good idea to eat vegetation from the woods unless you can identify the plants as being safe for human consumption.