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How to Build a Solar Water Collector

A solar water collector, or solar still, uses evaporation and condensation to distill purified drinkable water. In developing countries, large-scale solar distillation has shown the potential to provide a cost-effective, non-polluting solution to communities' needs for clean water for drinking and bathing. On a small scale, knowing how to produce up to a quart of potable water a day with only sunlight and a sheet of clear plastic is a basic survival skill under arid or marine conditions when water supplies may be scarce.

Things You'll Need

6 square feet of clear plastic sheeting without holes or tears, such as a drop cloth or large garbage bag
Watertight container, such as a bucket, cup or bag (optional)
Shovel (optional)
6 feet of plastic tubing (optional)
Tape (optional)

Instructions

- 1
  Search for damp ground for the site of your solar water collector. Since water runs downhill, the best sites are at the bases of hills and dry riverbeds. Look for basins where rainwater or runoff has collected in the past.
- 2
  Dig a pit in the ground about 4 feet in diameter and 3 feet deep, until you reach damp soil.
- 3
  Center your container at the bottom of the pit. To prevent it from tipping over, support it with rocks or place it in a smaller hole dug at the bottom of the pit. If you have no container, fold a watertight cup out of large leaves or a piece of plastic. If you have tubing and tape, position the end of the tubing in the container, tape it in place and run the other end of the tubing outside the pit.
- 4
  Cover the entire opening of the pit with the clear plastic sheet, and place a few rocks on the edges to keep it in place.
- 5
  Pinch or tie the end of the tubing closed so that water does not evaporate through it when it is not in use. The end of the tubing should protrude outside so it can be sipped like a straw without letting humid air escape.
- 6
  Center a small, rounded pebble on top of the sheet directly over your cup. Carefully push it down until it is at the bottom of an inverted cone with a 45-degree slope. The point of the cone should rest just over the cup. Water should be able to run down the sides of the funnel and drip into the container.
- 7
  Weight down the edges of the sheeting with rocks or soil to create an airtight seal.
- 8
  Wait several hours for sunlight to evaporate water from the ground inside the still, saturating the air with humidity. Water droplets will condense on the underside of the plastic and run into the cup.

Nature