Making a solar still enables you to obtain and purify water, even in very dry locations.
Build your solar still in the lowest, dampest area you can find - at the base of a hill, in a dry streambed or at the base of a dried-up gorge. This is where ground water accumulates and is the best place for gathering it.
Carry a sheet of strong plastic 6 feet by 6 feet, a cup or a container, and 6 feet of plastic tubing with you in your pack. In extreme survival situations you may be forced to make due with whatever you have. Understanding the principles of the solar still will enable you to adapt to your situation.
Dig a large hole in the ground, 2 feet deep and 3 feet in diameter. The idea is to dig down to damp soil.
Place your container, centered, in the bottom of the hole.
Place one end of your plastic tubing in the container.
Cover the hole with the plastic sheet. Use the dirt from the hole to weight the plastic surrounding the hole, so that no air can escape. Make sure the free end of the plastic tubing is accessible.
Use a small rock to weight the center of the plastic down over the cup, creating a cone over your cup with the point pointing into your cup.
Understand that as the sun heats up the soil, moisture evaporates and condenses on the plastic. This condensed moisture drips to the lowest portion of the plastic and then drips off into your cup.
Drink from your cup by sucking on the tubing. That way you don't have to disassemble your still to get a drink.
Realize that only pure water evaporates, so that in the evaporation process, most of the impurities are left in the soil.
- In very dry areas, green (non-poisonous) plants, damp forest litter, and urine can be added to your hole to dampen it.
- Dig deeper and wider in more dry areas.
- Use a solar still in emergency situations at sea to purify salt water into drinking water.
- Use the solar still to purify snow.