Wilderness Water Treatment Basics

  • Date:Mon, Jan 04, 16


Your pack can only hold so much gear. Out of all the items on your packing list, water is the most crucial. An early explorer would drink water from any stream or waterfall. Today, we know surface waters have dangerous microorganisms. Since there's no practical way to test water for microbes, it's best to treat it.


Types of Pathogens

Contaminants can take the form of microbes, chemicals or heavy metals. Generally speaking, microbes cause the most concern when treating wilderness water. Microbes divide into three categories based on their size: protozoa, bacteria, viruses.


The largest microbes and easiest to filter out is the Protozoa. They range in size from just over one micron microns (millionths of a meter) up to 15 microns. Giardia and Cryptosporidum are the best known microbes in this category. Cryptosporidium is a hardy cyst resistant to some chemical treatments. The microbe can last for several seasons in a pond or stream. To treat Cryptosporidium, use chlorine dioxide, mixed oxidants, UV light, and boiling.


In the next group, E. coli or Salmonella range in size from .2 microns to 10 microns. Bacteria can reproduce better than protozoa and spread by both animals and humans. It can contaminate a source of water in a greater way than protozoa. To remove bacteria from water, you can filter or treat it with chemicals, boiling or UV light.


Viruses such as Hepatitis or Norwalk are quite enduring and can survive months in the water. The concern to find viruses is greater in under-developed countries with poor sanitation. Yet, viruses can appear by any human presence. Since viruses are too small for a filter, you must use chemicals, boiling or UV light.


Water Treatments

The two terms often associated with treating water is filtering and purifying. A simple search will yield an assortment of filters and purifiers. You should find one suited for your particular activity and location. Day hikers need to keep chlorine dioxide tablets on hand for emergencies. Backpackers can use a pump filter for daily use.

Water Filters

Filters provide a quick way to keep your bottles and reservoirs full without a long wait time. The filter can handle many liters before it needs a replacement. If you are in an area known for waterborne viruses, you should use either a chemical or UV light treatment. The extra treatment can help since viruses are too small to filter.

There are several features to consider with filters:

Size and weight
Field cleaning and serviceability
Flow rate
Ease of use
Cartridge life
Direct connection to container

Water Purifiers

Purifiers are a mixed bag and range from small tablets to all-in-one bottle systems. Purifiers inactivate viruses and microbes by chemical, UV light and other methods, and can be used in conjunction with filters.


Iodine based treatments are effective on bacteria, viruses and some protozoa. Potable Aqua and Polar Pure are the best-known iodine treatments. To reduce the negative taste of iodine treatments, use neutralizing tablets. Do not use for long-term or if you are sensitive to iodine. Discard or use open bottles within one year.

Chlorine Dioxide

Chlorine dioxide treatments come as tablets or drops. The treatments are effective against viruses, bacteria and cysts like Cryptosporidium. Additionally, chlorine dioxide does not add a bad taste and may, in fact, improve the taste of the water. Be sure to give the chlorine dioxide gas four hours to breach their defenses. The Chlorine tablets come in a tough foil package and may need scissors. Once opened, use the table immediately.

Mixed Oxidants

The MSR MIOX purifier deactivates viruses, bacteria, and protozoa like Crypto in water by using a powerful dose of mixed oxidants. A brine solution is created from untreated water and salt through which the MIOX unit delivers an electrical charge, creating a mixed oxidant solution. The solution is then mixed with your untreated water and, after the appropriate dwell time (15 minutes to 4 hours depending on your target pathogen), the water is then safe to drink. The treatment does affect the taste of the water. The MIOX is rated for up to 200 liters per set of batteries and one ounce of salt.

Ultraviolet Light

Purify water with UV light, a quick and easy way to disable all microbes in water. Fill your bottle with water and push the button. Some units will disinfect one half-liter of water in about 48 seconds. UV light destroys the DNA of microbes rendering them harmless. UV light does not alter the taste of water. UV purifiers have found a niche with international travelers who are uncertain about the local water, bottled or not.


Boiling is perhaps the most low-tech method and also one of the most effective. If you have a stove or fire and a metal container, you can purify water by simply bringing it to a boil. The CDC recommends a vigorous boil for one minute, three minutes at altitudes over 6562 feet. Boiling will kill any microbes lurking around, including viruses.


Follow Directions

It is imperative that you read, understand and follow the directions for whatever treatment choice you make. Water turbidity and temperature often affect the efficiency and duration of treatment. Chemical treatments have shelf lives and, in the case of iodine, an opened bottle life. Filters should be cleaned and stored according to instructions to prevent bacterial growth in the filter. Filter hoses and prefilters should be packed to avoid cross contamination with "clean" filter components. Make sure that you know how your filter or purifier works and its effectiveness.


A separate but related topic is hand washing. It's been suggested that some post-excursion illnesses attributed to contaminated water should be blamed on improper hygiene instead. In any case, it's only smart and courteous to your fellow hikers to use hand sanitizer before preparing food or water as well as each time nature calls.


Be Prepared

It is important to be ready for your hiking and camping trips. At LifeView Outdoors, we care about your safety and equipment. Whether you're jogging through a forest in Nashville or up a mountain in Utah, be sure you have the gear you need. Check out our large assortment of outdoor apparel, gear, and tech.