How to Build a $1 Water Filter

In an emergency situation, access to clean water may be the most important factor in your ability to survive. In a predicament such as being lost in the wilderness, experiencing the fallout of a natural disaster, or finding yourself in a part of the world without potable water sources, it's vital to know the first step in obtaining clean water. A filter can be assembled for about $1 by anyone, anywhere, with some easily found materials.

Things You'll Need

• 2-liter bottle
• 5-inch-by-5-inch clean piece of thin, porous material, such as cloth
• Gravel
• Sand
• Untreated charcoal (optional)

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Instructions

• 1

  A 2-liter plastic bottle is inexpensive and effective for filtering water.

  Cut off the bottom of the 2-liter plastic bottle (or similar container) evenly and cleanly. Make sure the bottle is clean inside. Turn the bottle upside down so that the spout is pointing down. Remove the cap on the spout.

• 2

  A piece of cloth keeps the contents securely inside the filter.

  Place a scavenged piece of cloth (no cost) along the bottom of the container, next to the spout. The cloth will act as a barrier to the contents of the container coming out through the spout.

• 3

  Add gravel above the cloth barrier.

  Add a 2-inch layer of gravel to your container.

• 4

  Sand helps to filter particles from the water.

  Fill the rest of the container with sand until the whole bottle is about three-quarters full. The sand grains should be medium-sized: smaller than pebbles, but not so fine that the water cannot travel through the sand.

• 5

  Fill the container to the top with water. Place a container underneath the spout and wait for the water to travel through the filter. If the water looks silty, run the water through the filter more than once. Remember to purify the water by boiling or some other method, to kill microbes in the water.

• 6