The Basics of Water Filtration and Purification

 For Safe Water in the Backcountry or on Your Travels

These days it's difficult to find backcountry water sources not affected by some type of contamination. Additionally many popular travel destinations don't have reliable water treatment, meaning even tap water should be treated before drinking. As a local outfitter for hikers, campers, paddlers, and travellers, we stock many packable, lightweight treatment options so you can drink safely on your next adventure. Below is our guide to understanding waterborn threats to your health and how to avoid them while you recreate and travel.

What's in the Water?

Any given body of water may have at least one representative from the following 5 threats. We'll provide a description and some common varients of each threat and how to treat for them.

PROTOZOANS

Protozoa are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. A number of protozoan pathogens are human parasites, causing diseases such as malaria (by Plasmodium), amoebiasis, giardiasis, toxoplasmosis, cryptosporidiosis, trichomoniasis, Chagas disease, leishmaniasis, African trypanosomiasis (sleeping sickness), Acanthamoeba keratitis, and primary amoebic meningoencephalitis (naegleriasis).

At least part of their life cycle requires water. The good news is their size allows them to be filtered out of the water by all existing filters on the market, making them an easy threat to remove. 

Protozoans in the Backcountry: Giardia and Cryptosporidum.

Giardia infection (giardiasis) can cause a variety of intestinal symptoms, which include: Diarrhea, gas, foul-smelling, greasy poop that can float, stomach cramps or pain, upset stomach or nausea, and dehydration. Symptoms of giardiasis generally begin by having 2 to 5 loose stools (poop) per day and progressively increasing fatigue. Other, less common symptoms include fever, itchy skin, hives, and swelling of the eyes and joints. Over time, giardiasis can also cause weight loss and keep the body from absorbing nutrients it needs, like fat, lactose, vitamin A, and vitamin B12. Some people with Giardia infections have no symptoms at all.

How long after infection do symptoms appear? Symptoms of giardiasis normally begin 1 to 2 weeks after becoming infected.

How long will symptoms last? Symptoms generally last anywhere from 2 to 6 weeks. In people with weakened immune systems (e.g., due to illness such as HIV), symptoms may last longer. Healthcare providers can prescribe the appropriate antiparasitic medications to help reduce the amount of time symptoms last.

Crypto/Crytposporidium- Cryptosporidiosis symptoms generally begin 2 to 10 days (average 7 days) after becoming infected with the parasite. The most common symptom of cryptosporidiosis is watery diarrhea. Symptoms include: Watery diarrhea, Stomach cramps or pain, dehydration, nausea, vomiting, fever, weight loss.

How long will symptoms last? Some people with Crypto will have no symptoms at all. Symptoms usually last about 1 to 2 weeks (with a range of a few days to 4 or more weeks) in persons with healthy immune systems. Occasionally, people may experience a recurrence of symptoms after a brief period of recovery before the illness ends. Symptoms can come and go for up to 30 days. 

TREATMENT METHODS: Filtration, Purification, UV Treatment, Boiling

BACTERIA

Bacteria that occur in backcountry water and infect humans are the same that we are warned about in meat that has not been properly processed and cooked. The method of transmission is the same: animal or human feces contamination. People drinking water downstream from where livestock, or in some cases where wild animals have been defecating are also at risk of catching these bacteria. Generally only a small number of bacteria need to be ingested to cause illness. Some outdoors-people may also have a natural resistance to a particular strain of water-carried bacteria, while others may carry these bacteria in their intestines and infect others without showing symptoms (asymptomatic carriers). As with protozoans, bacteria are large enough to be filtered out by existing filtration, so it's easy to remove them from the threat list as well.

Bacteria in the Backcountry: E. coli, Shigella, Salmonella, and Cholera.

Bacterial infection can cause severe diarrhea, and fever. Other more severe symptoms such as nausea, vomiting, and abdominal pain are not unusual. Without antibiotic treatment some victims may suffer sufficient fluid loss from diarrhea to cause death.

TREATMENT METHODS: Filtration, Purification, UV Treatment, Boiling

VIRUSES

Viruses carried in water, that infect humans, have only one source, human feces from infected carriers. Waterborne viruses that cause disease include: rotavirus, caliciviruses-which now include the norovirus group with Norwalk virus, adenovirus, astrovirus, Hepatitis A & E, and enteroviruses (which include those that cause Polio and Viral-Meningitis). The two most common waterborne viruses in North America, rotovirus and noroviruses, are responsible for numerous outbreaks in restaurants each year of what is commonly called “food-poisoning”. Outbreaks of both have occurred from well or river water contaminated with raw sewage. Because of their small size, viruses cannot be removed through filtration and must be killed before consumption.

Viruses in the Backcountry: Norovirus and Rotovirus.

Norovirus infection can cause severe vomiting and diarrhea that start suddenly. Diarrhea, stomach pain and vomiting typically begin 12 to 48 hours after exposure. Norovirus infection symptoms usually last 1 to 3 days. Most people recover completely without treatment. However, for some people — especially young children, older adults and people with other medical conditions — vomiting and diarrhea can be severely dehydrating and require medical attention.

Rotovirus symptoms usually start about two days after exposure. Vomiting and watery diarrhea can last three to eight days. Additional symptoms may include loss of appetite and dehydration (loss of body fluids), which can be especially dangerous for infants and young children. Symptoms of dehydration include: decreased urination, dry mouth and throat, feeling dizzy when standing up, crying with few or no tears and, unusual sleepiness or fussiness.

TREATMENT METHODS: Purification, UV Treatment, Boiling

PHYSICAL DETRITUS

Twigs, grass, sand, silt, and now micro-plastics are all present in our water sources. While they will not directly make you sick, they can house other threats. They are what make water look dirty, and they are just not palatable to drink/consume. Becasue of their very large sizes relative to the other threats, they can easily be removed by filtration. These items in the water are what cause our filters to clog, making the process slower, to the point no water may pass through. If filtering dirty water repeatedly, rinse your filter well and make sure you have a back-up.

TREATMENT METHOD: Filtration

HEAVY METALS - PESTICIDES - HERBICIDES

This class of threat is relatively low in backcountry water but will be removed if your filter contains a carbon element.

TREATMENT METHOD: Filtration where the filter has a carbon element

Treatment Methods and How They Work

We've recommended 4 treatement methods to insure your drinking water is safe. Each is described below along with their pro's and con's. Oftentimes employing a combination of methods is best depending on the source or condition of the water.

BOILING 

Boiling is the classic method for making camp water safe. Boiling kills Protozoans, Viruses, and Bacteria. To do so, bring the water to a rolling boil for at least 1 minute (at elevations above 6,500 feet, boil for 3 minutes).

PROS: Low Cost; No additional equipment needed; No technology to fail

CONS: Must have a reliable fuel source; Boiling uses extra fuel that must be carried with you; You have to wait until the water cools before drinking; Detritius has not been removed

FILTRATION

Fast, effective and economical, filtering has become the #1 treatment method for backcountry travelers. Originally sold in pump form, the majority filters purchased today use gravity to do the work. Filter techology can either be fiber based (think super-duper coffee filters) or ceramic based (think a hard sponge with super tiny holes). Both offer similar effectiveness and both remove everthing but viruses from the water. Fiber filters tend to be faster, require less maintenance and replacement cartridges are less expensive. Depending on how dirty the water, a fiber filter is effective for around 100 gallons of water. Ceramic filters work for far more gallons as they can be repeatedly field cleaned, which is good as they generally plug up easier and produce clean water at a slower rate. They are best for remote, extended trips where it may not be possible to find replacment filters.

PROS: Easy to use technology; finished product is clean, debris free water; spores, bacteria, detritus, and heavy metals & pesticides are removed; filtering process is fast making it easy to clean larger volumes of water for camp use.

CONS: Must carry replacement filter or field maintenance kit in case filters plug up; Virusus not removed; Filter must be purchased and carried as part of your camping kit ; in and out hoses must be managed for cross contamination.

PURIFICATION

Purification offers the maximum protection against all three biological threats as proper treatment kills spores, bacteria, and viruses. Generally inexpensive and lightweight, purification is perfect for dealing with suspect tap water while travelling or in the backcountry where human or animal waste may taint your water source. Many campers carry purification tablets as a back-up to their filtration system or use it in conjunction with a filter to insure safe AND clean water.  There are now a few filters that offer purification protection. They tend to be smaller and good for treating personal drinking water rather than volumes needed for a campsite

PROS: Purification chemicals are small, light, and inexpensive means of treating all volumes of water. Kills all biological threats.

CONS: Treatment may take up to 4 hours before water is safe to drink; does not remove detritus so water will be dirty but safe to drink; most treatments leave a chemical taste in the water;

UV (Ultraviolet) Sterilization

The UV water disinfection process utilizes special UV lamps that emit UV light of a particular wavelength. These UV light waves have the ability, based on their length, to disrupt the DNA of microorganisms. These UV light waves are referred to as the Germicidal Spectrum or Frequency, the frequency used in killing micro-organisms is 254 nanometers (nm). During the UV water disinfection process, living organisms in water are exposed to UV light which attacks the genetic code of the microorganism and rearranges the DNA /RNA, eliminating the microorganism's ability to function and reproduce. If a microorganism can no longer reproduce, it cannot replicate, therefore it cannot infect other organisms with which it has contact. This process of exposing water to UV light is simple, effective, and destroys 99.99% of harmful microorganisms without adding any chemicals to water. This technology is commonly employed by municipalities or installed on home well systems to treat the your household drinking water. 

PROS: Small, light, and relatively fast; Neutrilizes ALL biological threats; gallon for gallon lowest cost treatment method; does not leave a taste to the water; no chemicals going into your body.  

CONS: Higher up-front cost than other forms of treatment; does not remove detritus so water will be dirty but safe to drink; powered by batteries so back-ups or a power source for re-charging needed; durability - the UV element is encased in glass and must be handled with care; if batteries die or unit is broken, you'll be without protection. 

Storing and Using your Clean Water

You've taken the steps to protect yourself and your campmates from getting sick, good job! Now how should you store and transport that clean water? 

WATER BOTTLES

The bottle is the classic, traditional method for storing and transporting water on the go. As such there are a lot of options in size, materials, how you drink from the bottle, colors, and so on! For backcountry camping we recommend at least one plastic bottle with measurement marks so you don't need measuring cups for cooking. Otherwise, the sky is the limit. The perfect bottle for you is out there somewhere!

RESERVIORS/BLADDERS

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