HowStuffWorks 2008

Water Collection Techniques

If you're stranded and there isn't a fresh water source around, then you need to get to work on collecting water. There are a few techniques to do this, and it doesn't hurt to set up more than one system. The more water you can collect, the better your chances of survival.

One pretty basic way you can collect water is to make a belowground still. To do this, you'll need some plastic sheeting, a digging tool, a container, a drinking tube and a rock.

  • Choose a moist area that gets sunlight for most of the day.
  • Dig a bowl-shaped hole about three feet across and two feet deep, with an additional sump dug in the center.
  • The sump should be flat and big enough to hold your container.
  • Place the container into the sump.
  • Put the drinking tube in the container and run it up and out of the main hole.
  • Place the plastic over the hole and cover the sides with rock and soil to keep it there.
  • Put your rock in the center of the sheet and let it hang down about 18 inches, directly over the container to form an inverted cone.
  • Add more soil on the edges for stability.

The moisture from the ground reacts with the heat from the sun to produce condensation on the plastic. The still forces the condensation to run down the plastic and into your container. You can also add vegetation inside the hole to increase the amount of moisture -- just make sure the plants aren't poisonous. Use the tube to drink directly from the container. If you don't have one, you can remove the container and reassemble it after. A good still can produce up to one quart of drinking water per day.

For better-tasting water, let it sit for 12 hours if you can afford to. You can also make a filter to remove any visible particles:

  • Find a large can, hollow log or plastic bag. Hollow bamboo will also work.
  • Punch 5-10 small holes around the base of your container and suspend it from the ground.
  • Fill it with alternating layers of rock, sand and cloth.
  • Use both fine and coarse layers, the more the better.
  • Pour your collected water into the filter and catch it in another container below.

HowStuffWorks 2007

The water should come through fairly clear, if not you can pour it through again. Add charcoal from your fire to remove odor -- just make sure you filter the charcoal out with some cloth. This method merely removes large sediment and improves the taste. You should always purify the water by boiling it.

In the next section, we'll look at some other techniques for collecting water.