Drinking Water 101: Water Pathogens & Water Treatment Methods

While spending time in the great outdoors water can be pretty scarce at times. Especially in an emergency situation, an unplanned extra few days or just plane and simply being unprepared. When planning a trip in the outdoors it is very important to think about what your water situation is going to be like while going out in the wilderness. Will you be around lakes, rivers, snowfields, glaciers or in the desert? Knowing the answers to these questions will  help you determine how much water you’ll need to pack in with you and what kind of treatment methods you’ll need to use.

If you’re planning a simple one day trip than your main source of water will most likely be the tap at home. For most people 1 ½ to 3 Liters of water is a good amount to stick with. Also depending on your activity level you might consider more. If you’re planning on being very active on your trip and doing a lot of hiking or climbing each person might drink up to 5 Liters a day. Then when you get to camping over a few nights you’ll need to calculate a few more Liters while in camp. Soon it’ll turn into a little too much to carry so supplies must be refilled by other water sources such as streams, lakes, snow fields, etc.

When you get to this point be aware of your surroundings so you’ll know what to expect with your water source. As Andrew Skurka mentioned in our Backpacking 5 Pro Tips post. Drink Smart: “The closer you are to a water source, like right below a snowfield or at the mouth of a spring, the less likely it is to be contaminated, because it just hasn’t had as many opportunities. A really large body of water will dilute contaminants, so the odds are lower of catching something. But if there are cattle or sheep around, I purify all my water.”

The main reason we treat our water is to protect us from the three main types of water borne pathogens:

Viruses: Hepatitis A is an example of a virus-caused disease that can be caused by drinking contaminated water. If your outdoor excursions are in the rocky mountains, snow capped peaks or in general North America. Then running into virus contaminated waters is a lot less likely as they are most often present in tropical waters and warmer climates. However it is always better to be safe than sorry and a simple chemical treatment or boiling your water will kill most viruses.

Bacteria: Unlike Viruses, Bacteria is present in mountain waters. Some of the harmful waterborne bacteria include: Salmonella, Campylobacter jejuni and Escherichia coli. Some of the Bacteria that can be found in water sources around the world can cause severe illnesse such as Typhoid. Like Viruses, most bacteria can be effectively killed with chemicals and can also be removed with proper filters because Bacteria is larger than Viruses.

Parasites: There are many large parasites such as Tapeworms and Flatworms but the two main Parasites that are a major health concern among Alpine travelers is The Protozoa Giardia lamblia and Cryptosporidium parvum (Crypto). Both of these Parasites are common in the backcountry waters of North America as well as worldwide. The illnesses caused by these parasites can take anywhere from two to twenty days to manifest themselves. Some of the symptoms you might experience are intense nausea, diarrhea, stomach cramps, fever, headaches, flatulence, and burps that smell like rotten eggs. Parasites are much larger so they can be filtered and boiling water kills them.

Here is a chart that shows the 5 main water treatment methods and their effectiveness, advantages and disadvantages:

This chart should give you a good visual at what will work best for you and your particular scenario during your next outdoor adventure. Not every situation or trip is the same, so no single method is the best. Depending on the terrain, how much gear you can pack or what part of the world you plan on adventuring into your methods of purifying your water source might be different from a person who is in a different area.

All in all, the most effective way to purify water is and always will be boiling water. However this is not always the most convenient to outdoor travelers which we all know. But boiling water still is the only guaranteed method of killing all of the pathogens in any contaminated water.