Humans can live for weeks without food. But death from dehydration can occur in days depending on your activity level and your environment. This means that getting water, as well as conserving the water you have, are two of the most important factors for survival.
Unfortunately, there is no universal surefire way to get the water you need, so the following is only a few ways to improve your odds.
Water always flows downhill. When looking for water it is unlikely that climbing in elevation will lead you to water. Also, going uphill will also take more energy and cause you to use more of the water that is in your body. The water that is in your body might be the only water you have within 100 miles, this means that you want to use as little as possible.
Peeing is better than sweating. Your body has already used the water in your bladder. But as your body heats up it is going to sweat in an attempt to cool back down. Especially in a desert environment where finding water is unlikely, you need to do everything you can do cut down on sweat. One way to do this is to take off your shirt and pee on it, then put it back on. This will reduce your need to sweat and it is much easier on your body than trying to reuse urine by drinking
Harvest Water From Plants
If there is vegetation where you are, especially grass, you can get quite a bit of water by taking off your socks and shoes and tying your socks around your legs just above your ankles. Then walk through the vegetation until your socks have absorbed all the water they can hold.
They can be wrung out in your mouth, or preferably in a container to reduce the amount of water that would be wasted. This should be done first thing in the morning before the sun evaporates the dew.
Make a ‘Survival Still’
Another option if there is less vegetation is to make a ‘survival still’, but you will need a few supplies.
First, dig a hole about 2 feet deep, and put a container in the bottom to fill with water. Surround the container with as much vegetation as you can (the vegetation is the source of water) while keeping the top of the container clear and the top of the vegetation several inches below ground level. Cover this with plastic, preferably clear plastic like food wrap, but a blue tarp or anything along these lines will do. Pile dirt or rocks around the edge of the hole, on the plastic, in order to anchor the plastic in place. Then poke a hole in the plastic directly over the center of the container. Put a weight on the plastic so that the hole you punctured in it will be lower than the rest of the plastic surface and will allow all water collected underneath to drip into the container. This is a great option because you can collect water passively while you are resting, building shelter, working on a signal for rescue or anything else.
Water is the most important element for survival. You might have access to it one day. Prepare now for what you will do then.