How to Filter Saltwater to Drink

Salt water is dangerous for human consumption because the high salt content can cause severe dehydration. If a fresh water supply is not available, salt water can be made safe to drink through the use of an underground solar still. The process of removing the salt from salt water is called desalination.

Things You'll Need

  • Plastic or metal bucket
  • Clear plastic sheet
  • Shovel
  • Rock
Show More

Instructions

    • 1

      Dig a bowl-shaped hole approximately three feet in diameter and two feet deep. Ideally, the solar still should be constructed in a place that is likely to contain ground moisture and has plenty of direct sunlight.

    • 2

      Dig a smaller, deeper hole in the center of the first hole and place the water collection bucket in it. Make sure the bucket will sit up without falling over.

    • 3

      Place the plastic sheet over the entire bowl-shaped hole and cover the sides of the sheet with dirt to hold it in place. Rocks can also be placed around the edges as weights.

    • 4

      Dig a trough around the hole approximately 10 inches away from the edge of the plastic sheet. Make the trough 10 inches deep and three inches wide.

    • 5

      Place a rock or other weight onto the plastic sheet directly above the water collection bucket.

    • 6

      Lower the plastic sheet so that the rock causes the center of the sheet to sag about 16 inches below the edge of the hole. Do not allow the sheet to touch the ground inside the hole. Place more dirt or rocks on the edge of the sheet to hold it in place.

    • 7

      Fill the trough surrounding the hole with salt water. The ground will absorb and filter the salt out of the water. As the sunlight heats the ground, the water will condense on the underside of the plastic sheet. The rock will cause the condensed water to drip into the collection bucket.