Survival guides · Water & Food

Make a Water Filter

WHEN TO USE THISClears out dirt and some germs. It does not make water safe — treat it afterward.

1. Gather

   • A plastic bottle with the bottom cut off — or cloth and three sticks.
   • Charcoal from a wood fire, crushed small.
   • Sand, and gravel or small stones.
   • A piece of cloth.

2. Build the layers

   
   • Bottle upside down, cloth over the neck.
   • Then, bottom to top: charcoal — sand — gravel. A few inches each.
   • No bottle? Tie three layers of cloth in a tripod — grass on top, then sand, then charcoal — and let it drip through.

3. Pour it through

   • Pour slowly. Let it drip through every layer.
   • First batch cloudy? Run it through again. 2–3 passes.

4. Then treat it

   • Always boil it, or use bleach or tablets, after filtering.
   • Filtering clears grit and some germs. Viruses and many bacteria get through.

Sources: CDC Emergency Water Filtration · US Army FM 3-05.70 Survival

General information to help in an emergency — not a substitute for training or professional care.