Backcountry Water Purification Techniques and Products
Treating Your Drinking Water On The Trail
For many years, I'd done a lot of hiking, but the majority of those trips had lasted a day or two at most. So I'd been able to carry all the drinking water I needed, straight from the tap to my water bottle or Camelbak, and never had to obtain extra supply from backcountry sources. Therefore, I never had to treat that water, either.
Thinking back, though, I was foolish not to have carried some method of purifying water, just in case, even on those shorter hikes.
Of course, when it comes right down to it, better to drink when you have to and worry about treating the after-effects AFTER. Dying of dehydration is much worse than having the "goon clutch," as my dad used to put it. But, better yet, go prepared and avoid the bathroom blues altogether.
When I went on my Appalachian Trail thru-hike (which you can read about here), with stretches of up to seven days between town stops, carrying water treatment products was no longer an option but a necessity. There were hikers who chose to play Russian roulette with their untreated drinking water, but, like most, I preferred to purify rather than puke (etc.).
Along the way, I tried a number of purification methods, which I'll share with you here, along with some I haven't used.
You've been hiking for hours. It's hot and dry and, boy, are you thirsty. And, lo and behold, the most beautiful, clear, babbling brook presents itself. So why not simply drop to your knees, cup your hands and drink?
Well, if bloating, diarrhea, headache, vomiting, flatulence, cramping, and a fever rolled into one miserable ailment sounds like fun to you, go for it. Take your chances and perhaps you'll be just fine. You'll find out for sure in about seven to twenty-one days.
But if you want to play it safe, assume that any water from untested sources is not safe to drink until treated.
There are two basic types of contamination. Biologically contaminated water contains microorganisms -- bacteria or viruses -- that can cause gastrointestinal infections.
Of the biological contaminants, Giardia, a microscopic parasitic cyst, is the most common and widespread. All surface water should be suspect, including clear-looking mountain streams. This intestinal bug is spread through oral-fecal transmission (um, that's basically poop to mouth) and is carried by humans and animals. Animals certainly aren't particular about where they relieve themselves and, in many cases, neither are humans, who often enjoy the view (and perhaps the background noise) of a lovely babbling brook while assuming the position over a cathole.
Cryptosporidium is the second most common microscopic critter in our backcountry sources, with the same mode of transmission and lovely symptoms as Giardia.
Toxic sources contain chemicals, such as mine tailings, pesticide runoff, gasoline and motor oil. Boiling, filtering, or chemically treating water can remove microorganisms but not chemical toxins. If you think a source is chemically contaminated due to its color or smell, find another source if at all possible. You'll need additional treatment methods to render such water potable.
The EPA says....
At least 90% of the world's fresh water is contaminated.
Boiling as a Purification Method
Back to Basics
PRO: Boiling is the most reliable water treatment method, effectively destroying contaminants.
CON: This method requires significant fuel, time and effort.
Of course, if you're going to boil, you'll also need fire starter, a pot and, unless a natural wood fire is your preference, a backpacking stove. Temperatures above 160 degrees Fahrenheit will destroy all the bad bugs within a half hour. Make that 185 degrees, and you can cut the time to just a few minutes. Fact is, once you get to a rolling boil -- 212 degrees F. at sea level -- it's okay to drink. Even at high altitudes where the boiling point is below 212 degrees, the water is still hot enough to have destroyed any unwelcome organisms. As a general rule, if you bring water to a full boil for one minute, it's safe.
Of course, then you have to wait till it cools down, unless you're having a hot beverage.
Note: If you have to use water contaminated with algae or particles, it's advisable to pre-filter with a layer or two of cloth. Bandannas are handy for straining (not to mention a number of other uses). But try to avoid pond scum, which may contain toxins that can kill animals and sicken people.
If you need a fast, lightweight backpacking stove for boiling and cooking, this is the one I recommend and use....
I've used this compact backpacking stove on many treks, bringing water to a rapid boil in as little as a minute. (Boiling times are somewhat affected by altitude.) Larger compatible pots are available for boiling more at one time.
Purify with a pump
PRO: Removes all organisms except the smallest viruses and yields instant potable water.
CON: Filtering requires pumping, adds weight to your pack, and is somewhat costly.
Types of Filters
There are two basic types of filters: membrane filters and depth filters.
Membrane filters contain thin sheets with specifically and evenly-sized pores that prevent objects larger than the pores from passing through. These filters are fairly easy to clean but do clog more quickly than depth filters. One example is the Katadyn Hiker Pro Microfilter.
Depth filters contain thick, porous material such as carbon or ceramic to trap particles as water flows through. Ceramic filters can be partially cleaned by back-washing. Activated carbon filters remove a range of organic chemicals and heavy metals, but the filters can be cracked if handled roughly, making them useless because untreated water can seep through the crack. An example of a depth filter is the MSR MiniWorks EX Microfilter. (More information on this and other water filters below.)
Filters Vs Purifiers
There is a difference between a filter and a purifier. Filters don't eliminate viruses, but some purifiers, such as the MSR Sweetwater Purifier System, pass the water through both a filter and a medium with an iodine compound that kills any smaller organisms that sneak past the filter. Such purifiers zap all microorganisms larger than 0.004 microns (which is really small!), but they shouldn't be used by those who are allergic to iodine.
Backcountry Filtering Basics
As a rule, filter the clearest water you can find. Dirty water or water with large suspended particles will clog your filter more quickly. As with boiling or virtually any treatment method, strain either through a pre-filter on the pump or a piece of cloth. If that's not an option for some reason and you have to filter dirty water, let it stand overnight so the particles can settle out.
Note: If the intake hose on a water filter has been in contact with untreated water, consider the hose contaminated and keep it in a separate baggie. Once the hose is dry, it's no longer a concern.
I used this filter on my Appalachian Trail thru-hike. It's not the fastest filter, but that's because it does its work well.
The MiniWorks EX has a ceramic element that can be cleaned repeatedly, with no tools required for disassembly. This lightweight and compact filter can pump one liter of water per minute. The kit includes the Miniworks EX, a stuff sack, a hose float, a scrub pad, and instructions.
Katadyn Pocket Water Filter
This first model is pricey for a good reason. It's super durable, dependable and lasts a long time, which is why it's popular with the military.
This microfilter features a silver-impregnated ceramic element that's effective against bacteria and protozoan under all sorts of conditions. Unlike disposable filters, the ceramic element can be cleaned several times in the field. And the element filters all microorganisms larger than 0.2 microns.
In fact, this filter can produce up to 100 times more water than standard filters.
Other features include a measuring gauge that indicates when you should change the filtering element, a cushioned base that makes it easy to pump on all surfaces, a prefilter, and a carrying bag.
I'm currently using this less expensive model and really like it. It's never clogged and pumps fast. The cartridge has to be replaced when it gets really dirty, because you can't clean it the way you can clean a ceramic cartridge, but it does have a removable filter protector that extends cartridge life in challenging conditions.
The replacement Katadyn Hiker Pro Replacement Cartridge has a capacity of up to 200 gallons, depending on how dirty the water is (how much sedimentation is in it),
Your Feedback On Filters - Please share your comments and help others decide
Do you use a water filter? Why or why not? Tell us which kind/s you've used and what you did or not like.
Yes, I Prefer a Water Filter
bestwaterdistiller: Yes, we need some best water filtration system to purify the water. The water contains so many contaminants.
markocampa: Yes I use water filter but not mobile,mine is at home and I am taking my water from my hom anywhere I go. :)
e-xplorations: Water filter are effective devices for purifying drinking water. But I would still suggest boiling water for a period of time. Its the primitive yet the most reliable water treatment I know.
TravelingRae: My group used the pump filters on the Chilkoot Trail. It was great! The water tasted good and I only pumped 1L at a time, so it wasn't exhausting. The device isn't that heavy either.
Renaissance Woman: I use the MSR MiniWorks.
jasonklass: I always use a filter. For years, I used an MSR Miniworks but now I use a gravity filer I made myself using a Aquamira Fronteir Pro. I hate pumping water.
anonymous: These filter overviews are great! I also recommend them on my blog http://www.backpackingwithbex.com - great!
anonymous: P.S. It was the Katahdyn Hiker Pro, to be specific. I recommend it.
anonymous: The Hiker filter we used on the Colorado Trail worked great. I'd rather use that than iodine or chlorine tablets, except as a backup.
Deb Kingsbury: I've used the MSR Miniworks and the PUR Hiker and have no major complaints about either. The Miniworks was (it's been a number of years since I've used it) heavier and slower, but it did its job. Now I use the lighter, faster PUR, along with a backup of either Polar Pure iodine or some Aquamira chlorine tablets. Sometimes I go with a filter bottle, though, instead of a filter.
anonymous: I have used the Katadyn Hiker PRO for several years now. I've never had the goon clutch. It's fairly lightweight, the filters are replaceable and it's a breeze to use. I would highly recommend it.
NC Shepherd: I use the Pur (now known as Katadyn)Hiker. I only needed two filter cartridges for the entire 2,000 AT miles plus the 700 I did into Canada. It works well enough that I wouldn't spend money on a different one even if it was smaller or lighter.
No, I Don't Use Water Filters, or I Have But Don't Like Them
sunriseyes: I have a Katadyn Hiker Pro. It's a great filter however I've been gradually moving towards ultralight. I've moved to Aquamira A-B drops. It does a great job, You don't get the chemical taste like iodine
BoyScoutPopcorn: We used the Katydyn pumps on High Knoll and Dolly Sods, and they worked fine. We used iodine at Northern Tier, and I like that process better. Faster results, less time and work, and less gear to haul.
anonymous: No, I keep my hikes short enough that a Camelback is sufficient.
The Christmas after my Appalachian Trail hike, I found a filter bottle in my stocking, which I thought was pretty neat. You squeeze or suck the water right through the filter.
PRO: The all-in-one bottle is compact, convenient, lightweight and simple.
CON: You pretty much have to submerge the bottle to fill it, so you may run into situations where you'll need to use a smaller cup to scoop or some other method to get the water from source to bottle. Also, the stream of water is fairly small due to the fact it has to be squeezed through the filter. So if you're really thirsty, you can't "chug."
There are many different types of filtration bottles on the market, varying in cost and number of refills before the filter should be considered worn out and the bottle discarded. Check with each manufacturer to get the details on what substances each filter will remove. I honestly don't recall what brand I had, but I know I used it for years and had no problems.
The Clear Brook Portable Filter Bottle, for one, is good for treating 100 gallons (or 750 refills) and capable of up to 99% reduction in all four areas of contamination, including:
- offensive tastes, odors, silt, sand and sediment;
- biological pathogens such as Giardia, Cryptosporidium, and other cysts and spores;
- chemical VOC's, PCB's, Agricultural SOC's, detergents and pesticides;
- and dissolved solids, as in heavy metals, aluminum, asbestos, cadmium, chromium, copper, lead, mercury, and radon-222.
The "No Leak" top, with a collapsible, pop-up straw, can be used either as a squeeze bottle or by drinking through the straw.
The product has been used and tested by International Red Cross, the U.S. Olympic Team, U.S. Coast Guard, and California State approved laboratories.
Yes, I've Used One and Liked It
Deb Kingsbury: I don't recall the brand (because silly me lost the bottle), but I received one of these as a gift, used it many times and really liked the convenience. The ONLY thing I didn't love about the filtration bottle I had was that it put out only a thin stream of water, so I couldn't chug. For sipping it was fine.
No, I Didn't Like It (or Wouldn't Use It)
NC Shepherd: As I said in the comments, I started my AT hike with a filtration bottle, but got frustrated because the pre-filter clogged so easily and it took forever to fill the bottle. I don't remember the brand.
Tastes like sucking on a kiddie pool! At least, that's what I thought when I used it, specifically Polar Pure iodine in solution.
PRO: Iodine is an effective disinfectant for Giardia when heating or filtration are not convenient.
CON: It makes the water taste funky and requires a certain amount of time, depending on the water temperature -- at least 10 minutes in warm weather and as much as eight hours in cold.
The unpleasant taste can pretty much be eliminated with pills made for that purpose or even with a drink mix, like Tang or Gatorade powder. Adding about 50 milligrams of straight vitamin C also has the same effect. I was told to add the vitamin C or drink mix after the treatment time, so the iodine doesn't adhere to the flavor crystals. Whether that's a fact or not, I'm not sure, but it sounded logical so I stuck to it.
Many people consider iodine to be a water treatment method for emergencies only, because iodine overload can cause problems if one has thyroid problems; however, those with normal thyroid function can tolerate high amounts of iodine. I used Polar Pure for about 4 out of my six months on the A.T. and never noticed any ill effects.
Note: If you have any thyroid issue, consult a physician before using iodine for more than emergency purification.
Iodine treatment products are lightweight and convenient for backpackers. The product below was my back-up purification method on the Appalachian Trail.
If you really want to get rid of the yellowy color and the "funky" taste of iodine-treated water, use this product instead. You drop in an iodine tablet and then one of the PA plus tabs to eliminate the funkiness.
Your Feedback on Iodine
Have you used an iodine product? Tell us why or why not and what you think.
Yes, I've Used Iodine to Purify Water
BoyScoutPopcorn: Used it at Northern Tier. Like I said before, it worked fine for us without any issues.
anonymous: I've used Potable Aqua on a couple of backpacking trips, and as long as I couldn't see the water (that lovely yellow) I barely noticed any taste. I didn't know about the (potential) dangers of iodine overload, so it's good to know about that, now. I love that these tablets are so small and light. While in camp, I always had two water bottles, so while one was purifying (half an hour according to the instructions on the bottle) I could drink from the other.
NC Shepherd: I always carry Polar Pure as a backup. I used it a few weeks on the AT when my filter got clogged. The taste didn't bother me...it was certainly better tasting than the water I filtered from that nearly dry swamp.
Deb Kingsbury: I used Polar Pure for four out of the six months I was on the A.T. The off taste didn't bother me, especially because I'd add drink mix (like Tang or Gatorade) after letting the iodine in solution work for 20 minutes or so. It was easier for me than stopping to take off my pack and filter, although I definitely had to strain through a bandana at times to take out the floaties. I still carry Polar Pure, at least as a backup.
No, I Don't Use Iodine
Renaissance Woman: I haven't used the iodine for purification. Now that I've read this article, I shouldn't (thyroid).
covenantguy lm: Never knew about it.
Vitruvian-man: Very informative. I would never think of this. Thank you.
SteriPen: Purifying Water with Ultraviolet Light
PRO: Convenient, quick and lightweight
CON: Murky water must be pre-filtered.
This is a fairly new process for treating water in the backcountry, with design innovations that have minimized the size and weight of these devices. The SteriPen Adventurer weighs just 3.6 ounces including the batteries and will purify 1/2 a liter (or 16oz) in less than a minute, or 1 liter (32oz) in 90 seconds.
The SteriPen destroys viruses, bacteria and protozoa, but it's not as effective in murky, sediment-filled water. So if you'll be treating water that isn't clear, it's best to filter the water first through the SteriPen Prefilter, which you can purchase separately, or a piece of fabric like a bandana or even a coffee filter before using the SteriPen.
I've used the Steripen on several backcountry trips and have found it reliable, convenient and fast. It's especially nice when it's really buggy -- mosquitoes, black flies, etc. -- around a water source. With the Steripen, I can fill my bottles and move away from the water to purify.
Designed specifically for outdoor and expedition use.
No pumping, no chemicals, no test strips, no timekeeping, no lubricating, and no replacement filters are required. Just press the button, dip the SteriPen into your bottle, and wait 90 seconds for it to purify -- up to 8,000 16-ounce treatments.
This water purifier zaps viruses, bacteria, and common protozoa using ultraviolet light to destroy the DNA of microorganisms, making them unable to reproduce and, therefore, unable to cause illness. The SteriPen is effective against giardia and cryptosporidium; pathogens that cause diarrhea, dysentery, hepatitis, and Legionnaire's Disease; household germs such as bird flu, E. coli, and salmonella; staph and strep; and risks from natural disaster, like botulism, cholera, smallpox, and typhoid.
You can purchase a Steripen prefilter if you'll need to remove sediment and particulates from murky water before purifying. It's made to fit the SteriPEN handheld products and gives you better--cleaner--end results. I've seen some hikers use coffee filters and bandanas as prefilters, as well.
Please Share Your Feedback On Steri-Pen
If you've used the Steri-Pen, did it work well for you?
Your Feedback On Filtration Bottles
Have you used a water filtration product? What did you think?
No, I Didn't Like It
adamf1313: I'm not sure how the pen would work in murky water. I prefer to use water condensation methods. All you need is a plastic bag and there are multiple ways to get pure drinking water.
PRO: It's cheap and readily available.
CON: You'll smell it (unless you can let it sit for a long time, i.e. overnight, so the smell can dissipate).
For this method, only use regular Clorox Bleach, not the Fresh Scent or Lemon Fresh.
First, let the water stand until visible particles settle out, then pour the clear water into an uncontaminated container and add the bleach. Mix well and wait half an hour. The water actually should have a slight bleach odor. If it doesn't, repeat the dose and wait another 15 minutes, then smell it again. Purifying small amounts requires only a few drops, so an eyedropper is a handy addition to your kit.
- 2 drops of Regular Clorox Bleach per quart
- 8 drops of Regular Clorox Bleach per gallon
- 1/2 teaspoon Regular Clorox Bleach per five gallons
If the water is murky, double the dosages.
Note: Bottles of bleach should be replaced every three months to ensure that the bleach is at full strength.
Your Feedback On Using Bleach To Purify
Have you used this method? Did you like it or not?
Yes, I've Used It and Liked It
SayGuddaycom: Used it on my boat a number of times and I have no complaints.
anonymous: Good and cheap.
No, I Didn't Like It (or I Wouldn't Use This Method)
anonymous: Although I have never been on a hardcore hike, I feel like this method could too easily harm the person drinking the water.
NC Shepherd: I don't think I'd use this. It's too easy to mix a toxic level of chlorine.
Other Chlorine Products
PRO: Chlorine can be used by people with iodine allergies or restrictions.
CON: Like iodine, treating with chlorine takes time, the length dependent on water temperature and sediment level.
Bleach contains chlorine in the form of sodium hypochlorite—other water treatment products contain other chlorine compounds. Halazone tablets are an example. Apparently reliable disinfection with Halazone requires 6 tablets per liter for 1 hour of contact, and the tablets rapidly lose effectiveness when exposed to warm, humid air.
Your Feedback On Chlorine
Have you used this method? Tell us why you prefer it or not.
Yes, I've Used This Method and Liked It
sunriseyes: This stuff is great! I love not having to pack the water pump. Saves on space and weight. Also while my buddies are still at the river bed pumping water. I'm all watered up and ready to go.
anonymous: I meant to say the tablets are expensive. The drops are not.
anonymous: The drops are very easy to use, but expensive. You really want the Aqua Mira drops, which work in 15 minutes are are much more economical. They sound a bit fussy to use, but our teenage Boy Scouts have no problem. No aftertaste, either. And the drops have a very long shelf life, so you don't have to worry how long they've been sitting in your garage. Both the drops and the tablets use chlorine dioxide, which is the only really effective chemical treatment.
Deb Kingsbury: This is my first choice for an emergency water treatment method. It's extremely light-weight and easy to use.
Grapefruit Seed Extract
A Non-Traditional Way of Purifying
I can't speak to the pros or cons of this product, because I know little about it. My husband does have a friend who's used it extensively on his backpacking trips and has never gotten sick, but I have no idea if this is directly attributable to the use of the extract. So this is not a recommendation, simply a heads-up that it exists and apparently has many applications, including water treatment.
Grapefruit Seed Extract (or GSE) is a substance derived from the seeds, membranes, and the pulp of grapefruit. It's considered highly effective in fighting infection and promoting health. GSE is used as a purifier, antiseptic, and preservative, with some researchers claiming that it's a superior antimicrobial to chlorine bleach, isopropyl alcohol, and colloidal silver.
For water purification, the recommendation is to add 10 to 25 drops per gallon of water, then shake and let stand for several minutes. The water will have a bitter taste to it.
For more information, visit AppliedHealth.com.
Your Feedback On GSE
Have you used GSE? Did you think it was effective or not?
Yes, I Used It and Liked It
anonymous: I used GSE in conjunction with my MSR mini-works filter on a recent trip in Oklahoma. Filtering water from a small stream that ran through vast amounts of cattle range. Never got sick from this experience, I'm sold on using GSE to purify backcountry water. Have also used GSE for other health related concerns and it has worked equally well.
anonymous: I love the idea of this. Think I'll get this as my backup water purification system.
covenantguy lm: Yip, I used it on a trip to east Malaysia and I didn't get the "travelers tummy" problem my friends got . You can read about it here
anonymous: Well, I didn't personally use it, but a friend of mine did and used it a lot and never had a problem, even with all the water he drank on many backpacking trips. So based on his experience, yes, I'd use this.
No, I Wouldn't Use It (or I Did But Don't Like It)
Renaissance Woman: I wasn't aware of this method for purifying water. I'm not sure that I would use this method given my other options.
Deb Kingsbury: I'd have to hear from more people who've successfully used this for water purification. Personally, I'll stick to the other methods above. For the most part, they're harmless and pretty easy to use, so I'm not looking for something new and, as I see, relatively untested.
Some Additional Tips for Treating Water in the Backcountry
- Always carry at least one backup method in case one fails or isn't so convenient. If boiling is your backup, be sure you have enough fuel.
- You don't need to treat water for cooking water or to be used for hot drinks as long as it comes to a rolling boil before you drink it.
- Be sure to use purified water for brushing your teeth. But you won't get Giardia from washing with contaminated water unless you happen to swallow it, so keep your mouth closed if splashing your face. The cysts have to get into your intestines to infect you.
- Consider using a collapsible backpacking bucket or tote to scoop water without disturbing the silty bottom of a stream or spring hole. This keeps the water cleaner for easier filtering. The bucket or tote can be lowered it into areas you may not otherwise be able to reach, and then you can take it back to camp to filter. The bucket is also handy for washing yourself and your clothes and dishes away from sources that could then be contaminated by the wastewater.
I carried a lightweight tote with me on the Appalachian Trail, so I could not only bring water back to camp for filtering but also have extra for cooking and washing. Buckets like these are good for murky water, because you can wait and let the sediment settle before filtering. This one has a 3-gallon capacity and comes with the zippered case you see next to it in the picture here. The bucket reduces to about two inches wide.
© 2009 Deb Kingsbury