Water Purification and what to know about it

Water that is not purified may make you sick, possibly even killing you. In a survival situation, with little or no medical attention available, you need to remain as healthy as possible. Boiling water is the best method for purifying running water you gather from natural sources. It doesn’t require any chemicals, or expensive equipment, all you need is a large pot and a good fire or similar heat source. Boiling for 20 or 30 minutes should kill common bacteria such as Guardia and Cryptosporidium. One should consider that boiling water will not remove foreign contaminants such as radiation or heavy metals.

Commercial purification/filter devices made by companies such as PUR are the best choices. They range in size from small pump filters designed for backpackers to large filters designed for entire camps. Probably the best filtering devices for survival retreats are the model where you pour water into the top and allow it to slowly seep through the media into a reservoir on the bottom. No pumping is required. On the down side, most such filtering devices are expensive and have a limited capacity. Filters are good for anywhere from 200 liters to thousands of gallons, depending on the filter size and mechanism. Some filters used fiberglass and activated charcoal. Others use impregnated resin or even ceramic elements.
Chemical additives are another, often less suitable option. The water purification pills sold to hikers and campers have a limited shelf life, especially once the bottle has been opened.

Pour-though filtering systems can be made in an emergency. Here’s one example that will remove many contaminants:

Take a five or seven gallon pail (a 55-gallon drum can also be used for a larger scale system) and drill or punch a series of small holes on the bottom.
Place several layers of cloth on the bottom of the bucket, this can be anything from denim to an old table cloth.
Add a thick layer of sand (preferred) or loose dirt. This will be the main filtering element, so you should add at least half of the pail’s depth.
Add another few layers of cloth, weighted down with a few larger rocks.
Your home-made filter should be several inches below the top of the bucket.
Place another bucket or other collection device under the holes you punched on the bottom.
Pour collected or gathered water into the top of your new filter system. As gravity works, the water will filter through the media and drip out the bottom, into your collection device. If the water is cloudy or full of sediment, simply let it drop to the bottom and draw the cleaner water off the top of your collection device with a straw or tube.

(If you have a stash of activated charcoal, possibly acquired from an aquarium dealer, you can put a layer inside this filter. Place a layer of cloth above and especially below the charcoal. This will remove other contaminants and reduce any unpleasant smell or taste).

While this system may not be the best purification method, it has been successfully used in the past. For rain water or water gathered from what appear to be relatively clean sources of running water, the system should work fine. If you have no water source but a contaminated puddle, oily highway runoff or similar polluted source, the filter may be better than nothing.