That stream you are standing over may look pristine and you are sure thirsty. A week ago, that water was pure but a rabid raccoon fell in the water and died. The rotting corpse is now pinned underwater just a few yards from where you stand and you cannot smell it, see it or taste it.
A drink here could be deadly, unless you have a way to filter the water.
So the question is, do you need a water filter system or water purification tablets? In an ideal world you would carry both that way no matter what the situation, you are covered.
Take a look at what each system does before deciding what to carry.
Portable filters range from straw-like devices you can easily fit in a pocket to large bags you fill with water. They can be mechanical, electrical or gravity powered. The larger the device, the more water you can screen until the filtering system must be replaced.
How much water you can filter also depends on how dirty the water is. Filtering from a clear trout stream will get you a lot more water than trying to pull from a muddy ditch. Manufacturers’ estimates of a filters life are based on clear water. Also, the smaller straw filtration systems are known to clog faster as well.
Larger systems come with a replaceable filter system. The smaller straw filter filters are typically use it and toss it. The smaller the water straw, the less water you will get from it before it loses its filtering efficiency.
Filters are measured in microns. A micron is about .00004 inches. To put that in perspective a human hair is about 75 microns. The smallest filter you can reasonably get in a portable system is .2 microns. Smaller is better.
● The filter system screens water. This is what you need if you must drink from muddy water or water with other suspended solids.
● The filter system takes out things like detritus, sediment, some pollutants like heavy metals, bacteria and some viruses, if you get the right size filter. The best filters screen stuff out down to .2 microns; make sure the filter hits that mark.
● Cholera, E. Coli and Salomonella are .2 to .5 microns in size, so you are on the very edge of getting rid of those bugs. Viruses can be as small as .004 microns and a .2 filter will not screen those out.
● The bigger the filtration system the more room it will take.
● Replacement filters also increase in size depending on your system
Water purification tablets kill the bugs in the water. That’s it. Most tablets incorporate chlorine as the purifying agent.
Tablets are a one and done.
● The tablets do a much better job of killing pathogens in the water than the filter systems.
● Tablets are small and last for a long time, up to years depending on the tablet.
● You can easily carry 100 tablets for 100 gallons of water in a space smaller than a 15-gallon water filter.
● They are easy to use. Drop it in the water, stir or shake. Anyone can do it.
● The tablets are not going to remove heavy metals, chlorine and suspected solids like detritus and sediment.
● If you dip muddy water and drop in a tablet, you will still have muddy water.
Some of the tablets can add an off taste to the water.
What do you need to carry? If you are out for a day hike where the water is plentiful and good, pack a filter straw or a sports bottle pump filter. A small prescription bottle made watertight by shoving it in a condom and tied off will hold enough purification pills to handle several gallons of water. If the water is questionable, carry water with you.
If you will be out for several days or for a SHTF emergency bug out bag, get a filter system that holds a few gallons at a time. Collapsible systems fold up very small. Fill the bag with the water, hang from a tree and let gravity do the work. A pack of purifying tablets should take up about the same amount of space.