Best water treatment system

6:07 a.m. on January 11, 2011 (EST)
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I run which provides comprehensive information on waterborne pathogens, contaminants and treatment systems.

I'm curious about what water treatment method / system different people use in different situations and why. Please post yours below.

Here's my system:

After more than 15 years and across a dozen countries, the treatment system I use has continued to keep me and my companions free from waterborne sickness.

My trips have largely been in mountain areas of North America, Western Europe, the Atlas Mountains of Morocco and New Zealand. Many of these areas have high quality alpine water sources though there is often a significant human and animal presence.

The greatest risks are from Giardia, Cryptosporidium and to a lesser extent bacteria and viruses. There is a small risk of helminth eggs or larvae because of the sheer number of tourists in some areas. There is also the possibility of chemical contamination from ranching, forestry and mining activities.

For treatment, I generally rely on a MSR WaterWorks II microfilter [I sometimes use a MiniWorks EX or a Katadyn Pocket Filter] with a ceramic element that has an absolute 0.5 micron pore size, a built-in GAC element and a secondary paper filter with an absolute pore size of 0.2 microns. In theory, this device should remove all microorganisms down to 0.2–0.3 microns including bacteria, protozoa, and any helminth eggs or larvae. The GAC element removes any offensive taste from the water although mountain water is usually clear and tasteless.

Since pathogenic viruses are generally only present in areas with people, I usually take the risk that the water is virus free or that viruses are clumped together with particles that can be filtered. On occassion I feel that specific water is risky because of a campground or climbers’ hut upstream, the prevalence of human occupation or because I'm drawing water from a river or lake draining a large area. In such cases I first filter the water to remove visible organic matter and silt if necessary. I then treat the water with Polar Pure iodine and let it sit for 20-30 minutes to kill bacteria and inactivate viruses before pumping it through the filter again so the GAC element can remove the iodine.

I've used this method effectively in many places including areas with huge herds of livestock [the Lake District in England] and lots of human faeces [Atlas Mountains]. This combination of microfiltration and halogen treatment is so effective that I'd recommend it for all but the most arduous conditions. The exception is areas with high levels of chemical or heavy metal contamination where no portable treatment system will be 100% effective. On my adventures, I rarely filter water used for soup, tea or coffee because boiling the water instantly kills all pathogens.


11:01 a.m. on January 11, 2011 (EST)
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I use a Microfiltre Vario from katadin mixed with a bit of purifier when in doubt. Scotch works fine but pristine is less expensive. That's for drinking. For cooking I use a fire for boiling water and a reusable filter that must look like your paper one. That's it.

11:57 a.m. on January 11, 2011 (EST)
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 i am such a diehard ultralighter these days that the only treatment i`ll use is aqua-mira, even if it kills me.

7:25 p.m. on January 11, 2011 (EST)
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Katadyn Hiker or Guide followed by Chlorine Dioxide, if I'm in a hurry or low on water I'll boil enough to meet my needs for the moment.


9:17 p.m. on January 11, 2011 (EST)
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I bought a SteriPen Classic after reading great reviews on it.  Worst $80 I have ever spent.  The thing will always work awesome at your house in a pint glass of tap water.  Once taken outdoors, however, it decides to go on strike and just plain not work.  I think I had a grand total of 9 uses on the lamp before the indicator light went out.  I sent it back and got a replacement, which again works well at home.  It will come out with me on an overnighter in the spring, and I anticipate I will just buy a filter anyways to save the headache.  And yes, I always bring tablets with me anyway, but I really don't want to use them unless I have to.

12:25 a.m. on January 12, 2011 (EST)
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SteriPen Adventurer with Solar Charger (and extra batteries) and a very fine coffee filter to filter out particulates. I haven't had a single failure/problem or illness after approximately 100 liters of treatments.

I now use a Camelbak Groove - a 22 oz, Carbon-Filter version of their "BetterBottle" to remove poor taste from certain water after I've run it through the coffee filter and used the Steripen.

4:24 a.m. on January 12, 2011 (EST)
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I rarely ever use any water treatment in the western US, with over forty years camping experience.  We exercise care selecting our water sources, however.  When I do use treatment it is one of the two-part systems that uses an ion solution to sterilize, and a oxidizer to precipitate the ion compounds out of solution.  Any water borne illnesses my group has ever experienced were due to poor personal and kitchen hygiene issues (read wash your hands silly!).  

6:56 a.m. on January 12, 2011 (EST)
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I have had a MSR miniworks EX for quite a few years and am very happy with it. I recently got a steripen adventurer off steep and cheap. So far it has not failed me, but I have read plenty of bad reviews and failure stories to have significant doubts about it.

Only time will tell. I bought the steripen for winter use where my miniworks runs the danger of freezing.

7:42 a.m. on January 12, 2011 (EST)
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I use a First Need XL Water Purifier.  During the winter I just keep a 60 hour shipping heater in the  pouch with it.  


11:09 p.m. on January 12, 2011 (EST)
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I was a diehard MSR miniworks fan for the longest time.  Living in AZ with the Colorado and mucky seeps had me well trained.  As I worked to lighten my load I decided when in the Sierra or Rocky Mtn highcountry or anywhere the water ran crisp and clear I could ditch the filter (and weight) and use aqua-mira drops or the katadyn chlorine dioxide tabs.

But 2 summers ago I hiked the JMT and met a guy using the aqua-mira frontier pro filter.  Perfect.  This is a two ounce pressure flow filter with a removable bite valve.  Screws onto platys, and just about any small head water/soda bottle.  I use a one liter platy, bite the valve, give the platy a squeeze and get big mouthfuls of filtered water.  No chemical taste, no 30 min wait.  Instant gratification!  Pull off the bite valve and you can also use this as a gravity filter. 

At ~$25 the aqua-mira frontier pro is perfect for clear crisp water conditions.  And when hiking around AZ I still use my MSR miniworks, and around Feb/Mar in Grand Canyon, when the river really does run red, I use the MSR with a sweetwater glacial silt prefilter. 

12:36 p.m. on January 13, 2011 (EST)
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Katadyn Pocket & Steripen Opti.


I like the "safety" of the rugged, easy-using, easy-cleaning, small filtering safety,


. . . and . . . that Sarah also uses it to protect her family!


Yes, it's HEAVY!  But I'll chug on down the trail, water condition be darn!


I also like my Steripen Opti.  It has worked well, no failures.  I use this for day-hikes only.

3:15 p.m. on January 13, 2011 (EST)
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Katadyn Hikep Pro, Or i boil water. I carry purification tablets for emergencies, but not for regular use.

6:37 p.m. on January 13, 2011 (EST)
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I meant that Laurie Ann March uses the Katadyn Pocket also, not Sarah.

2:04 p.m. on January 19, 2011 (EST)
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Used a First-Need and then a Katadyn each for a while.  Got issued an MSR when I was guiding.  Carried and used a discount-store $10 ceramic filter for a season or two.  They all worked fine as far as I know -- no one got ill.  But then who really knows if there was any bad bugs in the source?

Most of my packing is into sparsely-traveled areas -- at least by humans -- and much of that time is spent off-trail as far back in as I can get.  Because of that, and because I been drinking water in the wild since I was four-years-old, I've gone back to using my bandanna folded twice lately.  I do rinse the bandanna out first if it's been used. ;o)

I carry a Steripen when I'm in more used areas, places where there's been problems noted, and especially established camping grounds.  I make judgment calls on my source of h2o and use the pen if I feel it's needed.

My wife took her Steripen to Africa three times and never had a problem with it.  I have had mine get too cold winter camping and had to warm it up to get it to function.  Other than that, it lights up and I haven't had a problem with any bugs.

3:17 p.m. on January 19, 2011 (EST)
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Katadyn Micropur Water Purifier Tablets for short trips.

5:30 p.m. on January 19, 2011 (EST)
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For multi day back country use, I use a sedimentary (coffee) pre-filter followed by a Kataydn Pocket filter pump and granulated activated charcoal (GAC) post filtration.  If I'm really worried about the source, I use a Chlorine dioxide (Micropur, Aqua Mira) step following the sedimentation filter.  If I can, I'll just use a sedimentation filter and then boil the water instead of micro filtering.  I'm usually too lazy to do anything but carry some commercial reverse osmosis water in a pack bladder for day hikes.

The ultimate goal is disinfection of the surface water to a potable level and the effects of water contamination outweigh most any toxicity concerns.  For short trips, Chlorine dioxide use is acceptable to me.  It should be noted that there is some risk in using this chemical.  If you are pregnant, Chlorine dioxide has been shown to impair neurobehavioral and neurological development in rats exposed prenatally.  There is also some slight evidence of thyroid toxicity.  Chloride dioxide decomposes to chlorite and chlorate.  The effects of chlorite are primarily oxidative and the chlorite can be removed with a GAC filter, although the filters quickly overload and pass through can occur.  Chlorate is a more dangerous by product.  It is used as a weed killer and a large number of cases of chlorate poising have been reported with renal failure among the symptoms.  The oral lethal dose is estimated to be as low as 230 mg per kg of body weight, which is 100’s of times above the amount that one would likely ever see in regulated drinking water.  I have no idea of the residual chlorate amount that could be created using these back country products.  The chlorite ion is not easily removed from water once formed, and GAC filtering will not remove it.  Chlorine dioxide decomposes in sunlight, so you may want to leave the water in the shade during treatment.  The gas is self explosive at levels >10% in air.  Don't smoke around the water treatment bottle.  (References EPA Guidance Manual - April 1999 and WHO/SDE/WSH/05.08/86 - Chlorite and Chlorate in Drinking Water)

1:33 a.m. on January 23, 2011 (EST)
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I have been hearing about his method--has me very intrigued. The only major hang up here in the Seattle area/Cascades is that it would take the 6-8 hours for the sun to be effective. But it's a nice option to have....


Solar water disinfection, also known as SODIS[1] is a method of disinfecting water using only sunlight and plastic PET bottles. SODIS is a free and effective method for decentralized water treatment, usually applied at the household level and is recommended by the World Health Organization as a viable method for household water treatment and safe storage.

Exposure to sunlight has been shown to deactivate diarrhea-causing organisms in polluted drinking water. Three effects of solar radiation are believed to contribute to the inactivation of pathogenic organisms:

  • UV-A interferes directly with the metabolism and destroys cell structures of bacteria.
  • UV-A (wavelength 320-400 nm) reacts with oxygen dissolved in the water and produces highly reactive forms of oxygen (oxygen free radicals and hydrogen peroxides), that are believed to also damage pathogens.
  • Cumulative solar energy (including the infrared radiation component) heats the water. If the water temperatures rises above 50°C, the disinfection process is three times faster.

At a water temperature of about 30°C (86°F), a threshold solar radiation intensity of at least 500 W/m2 (all spectral light) is required for about 5 hours for SODIS to be efficient. This dose contains energy of 555 Wh/m2 in the range of UV-A and violet light, 350 nm-450 nm, corresponding to about 6 hours of mid-latitude (European) midday summer sunshine.


107px-U%2B2673_DejaVu_Sans.svg.png magnify-clip.png PET recycling mark

  • Colourless, transparent PET water or pop bottles (2 litre or smaller size) with few surface scratches are chosen for use. The labels are removed and the bottles are washed before the first use.
  • Water from contaminated sources are filled into the bottles. To improve oxygen saturation, bottles can be filled three quarters, shaken for 20 seconds (with the cap on), then filled completely and recapped. Very cloudy water with a turbidity higher than 30 NTU must be filtered prior to exposure to the sunlight.
  • Filled bottles are then exposed to the sun. Bottles will heat faster and to higher temperatures if they are placed on a sloped sun-facing corrugated metal roof as compared to thatched roofs.
  • The treated water can be consumed directly from the bottle or poured into clean drinking cups. The risk of re-contamination is minimized if the water is stored in the bottles. Refilling and storage in other containers increases the risk of contamination.
2:38 a.m. on January 25, 2011 (EST)
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..Solar water disinfection, also known as SODIS...

Sounds appealing, but not intuitive.  I have heard of this technique, but have yet to meet a single person who relies on it.  If solar ultraviolet disinfecting was an effective water treatment, why then do the experts discourage drawing from shallow brackish sources, when other alternatives are available?


8:42 a.m. on February 2, 2011 (EST)
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I'm always in area's with pristine water sources and rely on my Steripen Opti for purification.

I'll use a bandana if filtration is necessary,usually not.

11:15 a.m. on February 2, 2011 (EST)
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Solar water disinfection, also known as SODIS[1] is a method of disinfecting water using only sunlight and ...

While solar UV exposure does work, it is considered by experts in the field as an emergency method, suitable in time of major disaster (earthquake, hurricane, etc), when other methods are not available. By "experts", I mean the wilderness and disaster medicine people like Auerbach, Weiss, Tilton, and others who have been studying this sort of thing for decades.

While it does work, a lot of time and full sunlight is required. Like many other approaches, it does have its limitations - it won't remove chemical contamination (mine and industrial runoff, agrichemical runoff, etc), requires using closed containers that are transparent to UV, and other limitations. It is not a reasonable method to use for a weekend, or even month-long, wilderness trip.

What-worry, the reason it doesn't work for stagnant puddles is that the contaminants are introduced continuously - you need closed containers to keep from introducing new bugs. 

The bottom line is (apologies to the OP), there is no such thing as "THE best water treatment system." It depends on what is in the water. Different contaminants require different approaches. Most important for backcountry travelers, however, is personal hygiene - decontaminate your hands and the hands of your food handlers before touching any food. The real experts in the field of wilderness medicine all emphasize this over and over, and point to field studies that show that the vast majority of illness among backcountry travellers is carelessness (sometimes momentary) in personal hygiene.

I know the original question was "what do you use?" For me, the answer is dependent on where I am going. For short trips in mountains in the western US, I often just boil the water, but sometimes use my Katadyn Pro filter or SteriPen. In the Southwestern deserts for trips of a couple days, I carry jugs of water (heavy, but I don't have time or gear to test water sources from potentially contaminated "alkali pools"). Same in areas where I know there is mine runoff (parts of West Virginia, for example). In Tanzania, on the upper reaches of Kilimanjaro, the SteriPen, and when sharing the pool with the elephants and hippos, the Pur decontamination kit (uses flocculation), which I also keep on hand here in earthquake country). Though in many parts of western North America, I just drink out of the streams as I have all my life (not something I advise for most people who have not been living in the hills and 3rd world countries and developed resistance from early childhood - which probably means I am a "carrier").

1:09 p.m. on February 2, 2011 (EST)
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The SODIS method does work well for some situations, such as in third world locations where water is carried by hand or cart from streams and ponds to small villiages. In many of those situations fuel for boiling is limited, and electricity is in even shorter supply. Replacement filters and parts for purification systems are hard if not impossible for them to obtain. For those conditions the SODIS method is one of the most effective solutions.

5:11 a.m. on March 17, 2011 (EDT)
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I like and use the compactness and ease of a Steri-Pen Opti Adventurer after using the Steri-Pen Fits All Filter.


- Easy to use

- quick to use

- compact

- lightweight

8:30 p.m. on April 1, 2011 (EDT)
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If the water is clear, my preference is a Steripen while carrying tablets and a stove for backup. Steripens are finicky though. Once you learn their quirks, you should be able to keep them running, but I wouldn’t rely totally on a steripen or any other electronic device for that matter.

There are a couple of things I learned to keep a steripen running.

First, don’t use alkaline batteries. Lithium or NiMH work much better. If you’re doing multiple batches of water in a row, the batteries need some rest time between to recover. Lithium is best in this regard, but still not immune. Second, the two metal probes need to be dried, prior to starting. If they are wet, blow on them to dry them off. If it’s cold, keeping the pen and batteries warm also helps.

If the pen decides not to work, I have the tablets to purify water while hiking and the stove to boil water in the evening. Most of the time I’m carrying a stove anyway and the tablets weigh next to nothing.

Despite all this, the steripen is still my favorite method because of it’s ease. Just carry backup.

7:49 p.m. on April 7, 2011 (EDT)
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Steripen Adventure with the Solar Case is my first choice, although sometimes I'll bring the Sawyer gravity filter for fun. I also have an MSR Sweetwater that I never use anymore.

11:16 p.m. on April 7, 2011 (EDT)
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I was using the Kataydyn Hiker, switched to boiling the water after filtering out heavy particles while in camp or cooking meals/ coffee/ tea/ etc. That will kill everything anyway.

For hydration on the trail I use the Povidone-Iodine 10% Method. 1 quart of clear water with 8 drops of Iodine (enriched with vitamin C for taste), shake and wait 30 minutes. 

Some have complained about a bad taste with iodine, but if you enrich the mixture with Vitamin C, it removes all bad tastes associated with the iodine.

I have been thinking about the Steripen though.

12:17 a.m. on April 9, 2011 (EDT)
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Steripen Adventurer. I know some folks have themselves experienced plenty frustration with the steripen products, but I find it simply the quickest and easiest for me. My first few weeks on the AT a couple years back I contracted the dredded giardia somewhere in Georgia. So I was, to say the least hesitant in using a little blue light to purify my water. But this past summer after a few week trek, the thing didn't let me down once.

I find that for long treks, packing extra batteries is inevitable, but only needing to be changed once about every 7+ days. And that's with me using the heck out of the thing, along with a couple friends often begging to also use it as opposed to fiddling with their pump.

5:48 a.m. on April 9, 2011 (EDT)
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Katadyn guide, yes it is heavy but it connects to my camelbak system and is simple to use.

3:49 p.m. on April 11, 2011 (EDT)
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I've got a First Need XL as well and have found it to be worth the extra weight. I've also found the manufacturer to have pretty decent customer service when I had questions about the filter.


FWIW, I still managed to have a base weight of 15 lbs.

12:53 a.m. on April 12, 2011 (EDT)
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I love my First Need XL. I thought it was heavy before I realized I needed to carry an extra bottle of "water in treatment" in addition to my bottle of "water ready to drink" when using drops or tabs. The weight of that second filled bottle was always more than the filter, and I enjoy the convenience and taste improvement the First Need XL provides, so it was a no-brainer for me. It's a very durable, efficient, field-maintainable filter. I always bring AM tabs as a backup.

B.T.W. - Steripens and the like don't kill the baddies, they merely mutate them so that they ostensibly can't replicate, and then you ingest them, live and mutated. Regardless of the latest "super bugs" brought about by hyper-sanitation, I don't want to knowingly create, and then ingest, millions of mutated baddies just 'cause I want a drink of water.

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