You may know how to operate a water filter for your sink or a purifying filter for camping, but do you know how to make one from scratch when SHTF? When you're in a SHTF situation this is one skill that will come in handy. It's pretty easy to learn how to do, and you can find out how below.

If you're worried about the effectiveness of this method, don't be. It is almost equally effective as even the most advanced man-made water filters and the best part is that it doesn't cost a dime. It's essentially the same principles that goes into the natural filtration of water before it enters the water table, going through layers of rock and dirt to come out clean on the other side.

Don't forget the charcoal, though; charcoal acts as a magnet for the less-desireable chemicals and germs that may be in the water. If you don't use it you may be taking a huge risk. If you still aren't sure whether to trust the water after filtering, give it a once-over with some boiling.

This is a very helpful tip that everybody should be made aware of; there's no telling how many lives could be saved around the world if more people knew this simple method.