Build an emergency water filter

• 1). Get some charcoal. Charcoal will be the main filtering agent. If you have pure charcoal briquettes that contain only pure charcoal and a starch binder, and no other chemical additives, then you can use these. If the briquettes contain starter fluid or another contaminant, do not use them. If you happen to have access to refined activated carbon (perhaps a refrigerator water filter), then use that. Otherwise, you will have to build a fire. Use regular wood for the fire, not chemically-treated fireplace logs. Remove the logs from the fire when they turn black and crumbly. Do not let them burn to the point where they become gray or white ash.
  
  
• 2). Once the charcoal is cool, use a hammer or rock to crush the blackened logs or charcoal briquettes. Take your time with this step; it's important that the charcoal be crushed to a fine powder. You should produce enough to be able to fill up at least one-third of your container. The more charcoal you have, the better, because it will improve the efficiency and life of your filter or allow you to make multiple filters.
  
  
• 3). Get a container to house the filter. This can be an empty metal food can, a plastic two-liter soda bottle, a colander, or even some tree bark bent into a cone shape and tied together with rope. If there is a top (as with a plastic bottle), cut it off so that the container is open.
  
  
• 4). Take a knife and punch a number of small holes into the bottom of the container, unless it already has holes (as with a colander). The end result should look somewhat like a shower head.
  
  
• 5). Your filter will have five layers. Stuff the bottom of the container with a layer of coffee filters. If you don't have coffee filters, use any suitable alternative, such as cheesecloth, leaves, or grass. If you use leaves or grass, bunch them up as finely as you can to improve their filtering quality, and make sure they are unlikely to be contaminated by animal or human waste, or toxic chemicals. This layer should be about one-sixth of the total height of your container.
  
  
• 6). Add a layer of sand or soil on top of the coffee filters. Again, make sure it is unlikely to be contaminated by waste or chemicals. Pack it down a bit. After packing it down, this layer should fill up another one-sixth of the container.
  
  
• 7). Add a layer of charcoal. This should fill up one-third of the container. This is the heart of your filter. The other layers of the filter will only trap large particles like grains of sand or bits of debris. The charcoal, on the other hand, can trap much smaller substances, such as organic chemicals and most bacteria. This is because the carbon in the charcoal is filled with very small pores that will permit water to pass through, but will adsorb, or trap, the aforementioned chemicals and bacteria. This happens because those substances are much larger than water at the molecular level and will not fit through the charcoal's tiny pores.
  
  
• 8). Add another layer of sand or soil, filling one-sixth of the container. Do not pack it down yet.
  
  
• 9). Add a final layer of coffee filters (or leaves, etc.). Your container should now be full. Now pack down the top two layers with your hand, to create a space where you will pour the raw water.
  
  
• 10
  
  Collect your raw water. You can get raw water from any source, but flowing water is better than standing water. Rainwater is best, unless you have reason to suspect dangerous air pollution at the time of rainfall. Use common sense: Get water from higher ground, if possible. Choose clear water over murky water. Avoid water with trash or insects. And, if you have any choice at all, do not collect water from areas that are likely to be contaminated with human or animal waste, or toxic chemicals.
  
  
• 11
  
  Take the raw water and pour it into the filter. Do this a little bit at a time. Place your emergency water filter over your second container, which will collect the drinking water. The water will come out gray and murky and filled with bits of sand and dirt for a while. This is a natural process. Discard this discolored water.
  
  
• 12
  
  Eventually, clear water will drip out from the filter. In an emergency, this water is drinkable and much preferable to raw water. However, it is not likely to block viruses and small bacteria. If you have water purification tablets, you should use them.