A solar still is a special setup designed to use the sun’s rays to heat the air in a pit to drive evaporation out of the soil to a cooler surface of some sort. where the evaporation cools and condenses. The condensed water then falls into a container.
In the solar still, the sun heats the ground moisture, making it evaporate. The evaporation cannot escape the pit so it collects and condenses on the pit covering.
The condensation then drips into the cup.
- Dig a pit in the ground that is deep enough to reach damp soil (approximately 2 feet x 3 feet)
- Place a cup in the center of the pit
- Place the end of a 6 foot piece of plastic tubing in the cup
- Cover the pit with a plastic sheet, making sure no air can escape and that the other end of the plastic tubing is outside the pit
- Weight the plastic sheet down on each side using the soil from the pit or rocks
- Place a small rock in the center of the plastic over the cup so water will run into the cup after the evaporation condenses
- Use the tube to access the water in the cup
The pit should be dug wherever the ground is dampest. There must be sunny days for this water purifying method to work. Also, the size of the pit is dependent on the size of the available plastic sheet that must cover the hole. Finally, you can add vegetation to the pit, if desired. That will speed up the formation of water.
You can also build a solar still box, which is much more complicated than a ground solar still because it requires wood and construction. It is a project that could not be easily completed during a disaster and should be made in advance.