You do not need to be a Houdini to make water from air. You just need to know how to make condensation work for you. And because water is so critical for survival, knowing these tricks is well worth anyone’s time.
Make Plants Condense the Water For You
This technique will not provide all the water you need to survive, but it will certainly extend how long you can survive until help comes. Generally, people can live for three days without water, but if you are on an island, for example, the sun and wind will dry you out faster than if you were in a cool cave. That said, if you happen to be stranded without water but you are surrounded by trees or bushes and you have a few plastic bags, you can get the trees to give you some of their water.
Trees pull water from deep underground — deeper than you could dig — and they expire some of that water out through their leaves. If you put a plastic bag over a small branch you can actually collect water droplets as the tree breathes out the water. Each 12-inch square plastic bag will get you an only tablespoon of water or two each day. As a liter is 68 tablespoons, and you need about five liters a day, that does mean that you would need roughly 200 bags to stay well-hydrated. That’s definitely more plastic bags than a person would normally carry around, but when there is no other water available, even a tablespoon is most welcome.
Make a Solar Still
This will work anywhere, but if you are in a place where the days are hot and the nights are cold then it will work even better. Each solar still you make can generate about a pint of water a day, so if you have no other water source, that means you will need to make eight to twelve of these stills to get to the four to six liters of water a day that are usually required in survival situations.
One way to have that much plastic on hand is to carry ten large garbage bags in your backpack. Garbage bags can be unbelievably handy in the outdoors. They can be a poncho, a sleeping bag, a tent footprint, a signal, a trap and a water catchment system. Oh, yeah — and a trash bag. That’s quite a lot of use for less than an ounce of weight for each bag. For solar stills, you want a plastic bag sheet (you cut the bag on two sides to create an extra large sheet of plastic) that is about 36 inches square. If one side of the plastic is less smooth, put that side down. The extra surface area makes a difference.
To make the still, dig a shallow hole 18 inches deep and 36 inches wide. Put a pan down in the center of the hole. If you don’t have a pan you can also make a pan out of a sheet of plastic covering a dug-out part of the bottom of the hole. Weigh the top plastic sheet down at the edges with rocks and then very, very carefully, drop a large pebble in the center of the plastic sheet to create a low point. Your dish needs to be under the low point, so it can collect the water droplets as they condense and roll down the sheet.
One of the best things about a solar still is that you can use semi-polluted water. That’s because the water you will be drinking has evaporated and condensed, purifying itself. If you are at the beach, you could even set a still up in the high sand and distill the salt water into drinking water.