Solar Still

How to make a solar still

The solar still is a wilderness survival technique for gathering water in very dry locations, especially in the desert where finding water can be difficult. There are 2 essential components - a container to catch the water and a plastic sheet. A shovel or trowel wouldn't hurt either..

The basic principle is that solar energy heats the soil in a hole by passing through a plastic sheet. Moisture from the soil then evaporates, causing condensation to form on the plastic. Make sure when you are selecting your site for your still you look for a sunny location.

Construction

Dig a hole about 1m (3 ft) wide and 0.5 m (2 ft) deep.

Place a collecting can at the bottom. Cover the hole with a plastic sheet formed into a cone and hold it in place with rocks.

Place a small rock onto its center so the lowest point of the plastic sheet is directly above the container.

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The sun will raise the temperature of the air and soil in the hole, producing vapour. Moisture will condense on the underside of the plastic sheet and water will drop into the container. You need to open the still to drink the water that has been collected or alternative use some form of tubing.

The solar still only takes about an hour to build. If constructed correctly, it can yield about a litre (quart) of water a day.

Pure water

The still also has the ability to purify tainted water. In fact, it condenses pure water from just about anything. Read this interesting article about solar still.

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