A solar still will provide 100% pure water, and will not require purification or boiling prior to drinking. This technique will work just about anywhere, provided that there is enough sunlight to assist the process. Here are simple instructions how to build a solar still to extract pure drinking water from the earth.
Find, or dig, a hole in the ground
Place a water collection container at the bottom, and in the center, of the hole
Add live vegetation, in the hole, to improve moisture content
Loosely (not drum tight) cover the hole with a tarp or plastic across the entire diameter of the hole
Secure the covering around the top perimeter of the hole
Place a rock in the center of the covering so that the covering sags over the opening of the container
Ground moisture will condense on the inside of the plastic or tarp, and drip down toward the center and into the container
[How To Make a Solar Still] [Video 1] [Video 2] [Video 3]
Transpiration is the process in which plant life collects distributes and finally evaporates/dispels moisture from certain parts of the plant in particular the leaves. Transpiration bags work similar to a solar still, but with considerably less effort. A clear plastic trash bag is placed around a leafy branch, ideally in direct sunlight, and sealed tightly with cordage. Over the course of the day, it will collect water vapor, which will condense onto the inside of the bag, and run down to form a puddle at its lowest point. Drinking water right from the bag should be safe but it is best to filter and boil it first before ingesting.
Avoid gathering water from poisonous trees/plants to avoid illness or allergic reaction.
[Collecting water from plant life using a Transpiration Bag] [Video]
Green Bamboo and non-poisonous vines are good sources of fresh drinking water during late winter, spring and summer when the sap is running. Most people will recognize Grapevines but any vine that drips water when cut is a candidate. There are, however, four basic rules before drinking water from a vine:
1 - The water should be clear, not milky or discolored.
2 - The water should not have a foul odor.
3 - The water should have a mild woody to zero flavor/taste.
4 - Water should never be consumed from a vine known to be poisonous, like poison ivy, etc.
Cutting a vine to drink the water is actually a skill worth learning. The physics of it is similar to how a gas can works. On the back of most gas cans, there is a vent hole. As gas is poured from the can, it creates a vacuum inside the can that can slow the pouring. Opening the vent hole allows the can to draw in air that, in turn, allows the gas to flow more freely. This same priciple applies to drinking from vines. A crossway notch (hole) should be cut into the vine about 4-5 feet above where you will drink from. This will reduce the vacuum effect inside the vine and allow the water to flow out faster and in greater volume.
Reference: Drinking Water From Vines
A fog/dew catcher is a stretched out piece of mesh over copper piping which allows fog/dew to condensate into droplets of water and flow down to be collected into a barrel or bucket.
How to Make a Fog Water Catcher
Dew on grass and other ground plants can be gathered by dragging a cloth on a rope or tying cloths around the ankles, or stuffing them into pant pockets, and walking through a high grassy area. The cloth will soak up any dew from the grass or ground plants. Suck the collected moisture/water from the cloths or squeeze/wring it from the cloths into a container for drinking. Avoid dragging the cloths through poisonous plants to avoid illness or allergic reaction.
[Video 1] [Video 2]
It's obvious that water is produced from melting snow or ice. That doesn't mean they are safe to consume and melting them may not be as simple as one might think.
Medical Concerns: Eating [white] snow or clear ice will rapidly lead to hypothermia and the potential immediate pain of ice burn. Ingesting snow/ice turns it into water but the energy required is high and the cooling effect of that in the body makes it hard to stay warm. So, a little bit of snow/ice now and then isn't going to create a problem, but if a lot of water is needed, the body can't do that without serious consequences. Additionally, bacteria may be present in the snow/ice so they should be melted and the water boiled (5+ Minutes) to assure it is safe to drink.
Snow/Ice to Water Ratios: The ratio of snow-to-water is, very roughly 10:1 (10 inches of snow produces 1 inch of water) but there are lots of varibles that can change this ratio. The ice-to-water ratio computes differently but to keep it simple, 1 cup of ice equals in 0.92 cups of liquid water. Water is heavier than ice because water is denser than ice. Simply put, melting ice will be more efficient at producing water than melting snow.
Melting Snow/Ice should be done gradually. A little at a time is the way to go. Start with only a thin layer of snow or ice on the bottom of a pot — never pack it to the top. Snow is a good insulator, so if the pot is stuffed full of snow it can burn out the bottom of the pot. If you don't have a pot, wrap snow/ice inside a t-shirt or large bandana and use sturdy branches to suspend it above a fire. If on the move, placing a water bag full of ice/snow between clothing layers (not next to skin), or hanging on your back toward the sun, will melt as you travel.
Other Thoughts: Keep water from freezing by putting a container of it in your sleeping bag with you, making sure it, and you, are insulated from each other.
How to Safely Turn Snow & Ice Into Drinking Water
Obtaining Water from Snow and Ice