How to make purified water if you're lost in the wild

Finding potable water in the wild is a vital survival skill.

The availability of food and drinking water may not pose an immediate problem to the prepared hiker who has gotten lost in the wild. When unprepared hikers get lost or when supplies run low, simple survival skills like water purification can mean life or death. In the absence of common purification gear like iodine tablets or bleach, solar distillation may be the only way to obtain clean water.

Difficulty:

Easy

Instructions

Things You'll Need

• Sheet of plastic
• Bowl or other container

1. Find an area with moist soil. Look for healthy vegetation in a shaded area. Good plant growth and shade indicate the probable presence of moisture in the soil.

2. Dig a hole as wide as your container and place the container in the hole, right side up. Depth depends on the terrain, digging implements available, and moisture content of the soil. Dryer conditions mean a longer wait time to collect potable water.

3. Stretch plastic over the hole. Any plastic will suffice, including a piece of tarp, plastic bag or backpack lining, providing it has no holes, rips or other defects. Secure the edges of the plastic with rocks, loose soil or other materials that help maintain a tight seal over the hole.

4. Place a small rock in the center of the plastic. The goal is to form a funnel by weighing down the plastic.

5. Monitor the container periodically for water. As the temperature under the plastic rises, moisture from the soil will evaporate and form condensation on the underside of the plastic. The funnel shape ensures water droplets run along the underside of the plastic and drip into the container, rather than absorbing back onto exposed soil.

Tips & Warnings

• Shade ensures soil with high moisture content, but sunlight helps speed the temperature increase needed to form condensation.

• Solar distillation takes longer than any other form of purification, but requires the least materials.

• If other options such as boiling or adding purification chemicals exist, pursue these options first.

• Other primitive options for cleaning water in the wild exist. Purifying by filtering water through cloth and sand, for example, removes sediments and other impurities. Filtering does not eliminate microorganisms, bacteria, or chemical contaminants. Distillation is the safest primitive option.

References

• Louisiana State University: Emergency Water Purification
• Wilderness Survival Skills: How to Purify Water

Resources

• Nature Skills: Water Purification Process