DIY SURVIVAL WATER FILTER
You will see on the web instructions on how to make your own DIY filter, mostly all specify the use activated charcoal to filter out harmful pathogens and chemicals. You may be out in the wilderness, do you have activated charcoal on you? probably not. Fortunately, there are a couple of ways to make a water filter without it.
To make a water filter without activated charcoal, you need replacement materials that has pores large enough to allow water to pass through, but small enough to catch sediment, pathogens, or other impurities. Sand is one of them and ceramic is another. I will show you the sand example.
These are the materials you will need in order to construct a sand bottle filter.
A clear plastic bottle.
One coffee filter or strip of cloth, bandana etc.
A rubber band, paracord or cordage
There is a few steps need to make a DIY water filter
Cut the bottom of the bottle and turn it upside down
Put some cloth in the bottom first, this is to stop the materials coming out, then wrap some cloth of a coffee filter over the bottle cap and secure with a band or cordage
Fill with some fine sand like the image
Then fill with coarse sand
Then top with some gravel or stones
Pack it down
Put a container underneath to catch the water
Then add your unfiltered water to the top
There you have it, a DIY water filter. As you know, this is just to clean the water, the same as a Millbank bag.
You must sterilise the water after. DO NOT drink it straight away. Use chemical treatment or boil it to a roiling boil. Better to be safe than sorry.