Outdoor Water Treatment Options - Buyers Guide

Posted by Mountain Equipment Chatswood Staff on

Outdoor water treatment options buyers guide header image

The quality of a water source in the great outdoors may often be questionable, giving us good reason to use some sort of water treatment before hydrating to save ourselves a midnight bathroom dash. There’s no doubt that the multitude of water treatment options available on the market are enough to send your head spinning, so here we demystify exactly which options are most suitable for your desired outdoor adventure – whether that’s a backup water supply for a day hike or a full-blown expedition.


Pathogens


To understand the best water treatment option for you, you first need to understand the different types of pathogens. These are:

  1. Parasites – the largest type of pathogen which includes giardia, tapeworm and protozoa
  2. Bacteria – the next largest nasty which cause illnesses such as cholera or salmonella
  3. Viruses – the smallest microorganism which requires special attention (more information below)

    Knowing the difference between these pathogens is vital, as not all water treatment options eliminate all three types of pathogens. Different water sources, different areas or countries pose different risks when it comes to possible pathogens in the water. Know where you want to use your water treatment device and what the risks are – then you can make the best choice of water treatment.

    As a generalisation, most of the types of water treatment options discussed below will treat for parasites and bacteria, however the particular nasties that you should do extra research on whether you need protection from are viruses and the parasite cryptosporidium. 

    Viruses are carried in humans and animals and spread in all the ways you learnt about in primary school but of particular importance to this article is spread through excrements. If you are hiking or travelling anywhere that human or animal waste runoff can end up in a water source then viruses should be considered a possibility. It's also worth nothing that in third world countries, even town or city water supply through taps have been known to carry viruses. So using water treatment methods discussed in this article aren't just meant for the wilderness. 

    Cryptosporidium is a parasite but what sets it apart from others is that its shell is particularly hardy. This means that it can survive for a lot longer outside of a hosts body than other parasites and even in very cold and frozen water sources. Like most parasites it is spread from humans and animals mainly through runoff from feces, but also worth noting that it's more commonly caught by just shaking a dirty hikers hand. 


    Filters vs Purifiers


    Water treatment can be classed into two main types: filters or purifiers. Filters work in eliminating pathogens by physical means (think a small sieve with holes of 0.2 microns). This is very effective in blocking parasites and bacteria, but the filtration holes are too large to prevent viruses from flowing through. On the other hand, purifiers are effective against all three types of pathogens. This may involve using filters with very small holes (less than 0.1 microns), or by chemical treatment or UV light. It is important to note that while purifiers may kill or sterilize all pathogens, chemical or UV type treatments obviously do not remove debris from the water. So, in some extreme cases where you suspect all three pathogens and the water contains a lot of suspended debris, you may have to utilize both methods, even if that means a simple paper filter.
    As a general rule of thumb, filters are fine to be used alone in remote wilderness regions where viral contamination is unsuspected, whereas purifiers are necessary in areas with human or animal presence.


    Types of Water Filters


    Gravity filters


    After filling the bag with the contaminated water, simply hang it up on a tree branch and let gravity do the work for you – filling your bottle from the hose as the filter works its magic.


    Example: Katadyn 6L Gravity Camp

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    Pump filters


    These rely on a bit of manpower. Place the hose of the filter in the water source you wish to treat, and pump the filter body. This allows you the versatility of drinking straight from the source or filling up your bottle.


    Examples: MSR Trailshot Microfilter, Katadyn Vario Microfilter

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    Straw Style Filters


    These filters are the epitome of convenience - place one end of the straw in the water source and drink straight from it!


    Example: GoFreshWater Go Straw

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    Types of Water Purifiers


    Chemical Purifiers


    The most commonly used chemicals are chlorine dioxide, chlorine and iodine. Chlorine dioxide is the more effective option – eliminating all three pathogens in either tablet or a two-part liquid form. Chlorine/iodine tablets are effective against all pathogens except for cryptosporidium, so it is recommended to use a filter as well if crypto contamination of the source is suspected.


    Examples: Lifesystems Chlorine Dioxide Droplets, Katadyn Micropur Forte Tablets

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    UV Purifiers


    These battery/USB charger operated devices sterilises 99.9% of ALL pathogens in a matter of minutes. Turn the device on and stick the UV lamp into the water you wish to treat, giving it a bit of a swirl. The lamp will turn off after your selected time (according to the water volume) is up, meaning the water is now safe to drink.
    Note: If the contaminated water is particularly murky, we recommend using a prefilter before treating with UV, as particles may shield pathogens from the light.


    Examples: Steripen Classic, Steripen Ultra, Steripen Aqua, Steripen prefilter
    (The difference between Steripen models usually comes down to lamp life, number treatments per battery life, complexity of screen display and the method of recharge (battery/USB))

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    Boiling


    This simple but highly effective method eliminates all pathogens. It does, however, get a little bit trickier at altitude as water boils at a lower temperature (due to the change in partial pressure of Oxygen), which means that boiling time must be extended to ensure all pathogens are killed. It can also be time consuming in cold or windy conditions, or if it’s hot and all you want is a refreshing mouthful of cool water.


    Water Treatment Device Comparison Chart

     

    Pros

    Cons

    Gravity Filters

     

    • Lightweight and foldable
    • Short filtration time
    • Suitable for large groups
    • Most do not filter viruses
    • Requires something to hang it on
    • Slightly larger than other filters

    Pump Filters

       

    • Compact
    • Most models are lightweight
    • Long Lasting
    • Requires manpower
    • Most do not filter viruses

    Straw Style Filters

     

     

    • Affordable
    • Simple to use
    • Highly convenient 
    • Lightweight and Compact
    • Some models remove viruses
    • Most drink straight from the source
    • Lower lifespan than other filters
    • Not good for groups or bulk supply of water
    • Can't store bulk water in bottle or bladder

    Chemical

       

     

     

    • Cost effective for shorter trips
    • Chlorine Dioxide is effective against all pathogens
    • Weighs next to nothing
    • Tablets can be used on the go
    • Chlorine dioxide may take up to 2 hours to kill cryptosporidium
    • Chlorine dioxide requires mixing
    • Iodine/chlorine not effective against cryptosporidium
    • Does not remove debris

    UV Light

     

     

    • Highly effective against all pathogens
    • Short purification time
    • Compact
    • Requires batteries/USB charging
    • Lamp may be fragile
    • Requires prefilter if water is murky
    • Does not remove debris

    Boiling

     

     

    • Affordable
    • Effective against all pathogens
    • No learning curve
    • Can also be used for coffee while you’re at it!
    • Extra gas may add to weight
    • Not as reliable at altitude
    • Somewhat inconvenient and can be quite time consuming
    • Does not remove debris

     

     

    Which Water Treatment is Best For You?


    So now you have a good idea of the pros and cons of each major type of water treatment option, it’s time to do some research on your next outdoor adventure to determine which one is best for you. Questions you should ask yourself are:

     

    • What are the water sources like where I am going and what is the general advice on using them?
    • Are there known pathogens in the water sources where I am going?
    • Are there human or animal populations near the water sources, or is it a very remote area?
    • Are the water sources general clear, running and debris free or will there be a lot of suspended matter?
    • How large a group am I treating water for? Just me, couple or many?
    • How much is weight an issue for me or is longevity and function more important?
    • Are there safe water sources and this is just for a backup in case I run out in between camps, or will I be using this for ALL my drinking water?
    • How long will I be drinking water treated by these methods? Just a couple days or possibly weeks/months?


    Having a good think through these questions and then re-reading the comparison chart above will give you a good idea about what type of water treatment is right for you and your next adventure.

     

    By: Stephanie Ho


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