Having clean drinking water is essential to your health! It can also be something that a lot of us take for granted. It’s sometimes easy to forget that foreign countries may not have the same level of hygiene and maintenance on their water sanitation systems. Alternatively drinking pure water from clear-flowing stream is one of the simple and fundamental joys of being in the outdoors.

Unfortunately even some of the cleanest, purest water on earth is still susceptible to contamination from microscopic pathogens (Disease-causing agents). Birds, animals and humans all have an impact. You need to play it safe with water in the wilderness, and whilst travelling because it might end up being the worst place to be if you develop a sudden illness.

There are three main types of water contaminants

1. Suspended matter (dust, silt, leaves etc.)
2. Chemical (pesticides, insecticides, fertilisers etc. which include heavy metals)
3. Micro organisms (bacteria, protozoa, viruses)
Each one of these contaminants can be present in a range of sizes and concentrations; therefore we can apply various filtration and purification methods to remove them. Some methods cover most contaminants but not all, while others will need to be used in combination with each other to provide the safest possible outcome.

Purification Methods

Boiling- Boiling your water is an effective way to deal with micro organisms as most micro organisms won`t survive in temperatures greater than 60 °C, therefore boiling water for ten minutes is a good way to ensure that these insidious little creatures don’t enter your system. Unfortunately boiling doesn’t really help with suspended matter and other filtration methods should be used in conjunction with boiling for the best water quality results.


Chemical Treatments- Exposing water to purifying chemicals such as iodine, silver or chlorine is believed to kill bacteria and viruses, but not all protozoa. Giardia and Cryptosporidium are resistant to chemical treatments. Giardia and Cryptosporidium are larger than the pore size of most microfiltration devices, so chemical purification in conjunction with microfiltration is recommended if you wish to be absolutely certain that the protozoan have been removed. Also purification tablets will not help remove suspended matter or flavours. Purification tablets do take time to be effective, read the directions carefully and follow them. Water Purification tablets such as the Katadyn Micropur Tabs.


Silver ions combined with chlorine make Katadyn Micropur extremely effective

Note: Iodine is a very effective poison, including to humans in larger quantities. Pregnant women should not use it or people who may be allergic to it and it can be unhealthy for people who use it for periods of longer than 14 days. Follow manufacturer instructions closely when using iodine or chlorine.

UV Sterilisation- UV Sterilisation products such as the Steripen and Camelbak All Clear use ultraviolet (UV) light technology to purify water, destroying more than 99.9 percent of bacteria, viruses and protozoa such as Giardia and Cryptosporidium. Purifying water with UV light offers many advantages.


In addition to being safe and effective, UV light does not alter the taste, pH, or other properties of the water, and works without the introduction of chemicals to the water. Again suspended matter remains in the water so microfiltration used in conjunction with UV sterilisation will give you the cleanest results.


Microfiltration- These are the most popular solution to water contamination, microfilters are specifically designed hand held devices that clean water via a mechanical process, forcing it through a fine porous internal element housed within the filtering unit. Some units contain activated carbon as their main filtering medium, due to its high level of micro-porosity; just one gram of activated carbon has a surface area in excess of 500 m2, and can help remove some chemicals and tastes.

cross section of a Katadyn hiker pro, showing the activated charcoal filtration media

Cross section showing the activated carbon contained inside.

Standard microfiltration devices will remove suspended matter, bacteria and protozoa, but not viruses. Viruses are too small to filter effectively and require further purification. Used in combination with purifying tablets, UV sterilisation, or boiling, microfiltration devices are very effective.


Katadyn Hiker Pro with pre-filter/float andEasy Fill bottle adaptor

Other deciding factors:

Simplicity of use- UV sterilisers (e.g. Steripen & Camelbak All Clear) and chemical treatments (e.g. Katadyn Micropur Tabs) are the simplest form of purification as far as ease of use as you can stop at a tap or a flowing stream, fill your bottle, add your purification, and move on, no pumping, no setting up a stove and waiting for your water to cool.

Speed of use- UV sterilisers (e.g. Steripen & Camelbak All Clear) are the fastest method of purification, taking only a minute or two per bottle. Using a microfiltration device such as the Katadyn Hiker Pro or the Katadyn Vario is more of a task but will give you water free of suspended particles, bacteria and protozoa in between 1 and 2 litres per minute depending on the rate of the particular pump. Katadyn Micropur Tabs will take between twenty minutes and an hour before they are totally effective. Boiling will take however long it takes for you to set up your stove boil the water and cool the water.

Longevity- Microfilters, Chemical treatments and UV Sterilisers have a finite capacity. Microfilters can become blocked with fine particles over time but they can be cleaned and replaced. Chemical treatment tabs have a standard shelf life which is typically stated on the packaging. UV sterilisers are an electrical device that run on batteries each product in the range will treat differing amounts of water.


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