backup water treatment

8:53 p.m. on September 8, 2009 (EDT)
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Im wondering, were my water filter (MSR sweetwater) to somehow become disabled on a trip, what would be a good backup option. I've read here, and have heard friends' experiences with failing/breaking water filters. I know that chlorine dioxide or iodine tabs would do the trick. My filter, however, came with "sweetwater solution" (bleach) - concentration of 3.5% Would it be suitable to just treat the water with that, or should I spring for one of the two others? Thanks.

10:08 p.m. on September 8, 2009 (EDT)
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I carry tablets in my emergency sack. I'm kinda worse case scenario, where if I loose the whole filter in a river, forget it, bust it, falls off a cliff or a gator eats it I still have tablets in my pack. When I'm backpacking I always have a secondary backup (in a separate orange waterproof stuff sack) for all the basic necessities to survive. I call it the "Oh $#!T" sack.

Getting back to your post, I guess the question you need to ask yourself is are you comfortable with how much the sweetwater solution can treat, and on how many seperate occasions.

10:17 p.m. on September 8, 2009 (EDT)
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If I'm not badly mistaken the Sweetwater chemical treatment is chlorine dioxide.

One popular back up method is to take a coffee filter (or 2), or a bandanna works also to filter the water with. This method will only remove sediment. Additionally you can let the water set for a while in a container and allow the sediment to settle to the bottom, then you can slowly pour the water through your bandanna or coffee filter. Then you use the chemical treatment according to the manufacturers instructions.

With chemical treatment only you will have to wait about 4 hours depending on water temp. and clarity.

Or you can "boil" although it is not necessary to reach a rolling boil.

But best of could read a great article by Bill Straka right here on Trailspace, it is in 4 parts and will give you all the info you need!

Here is a link to the first part:

What you are looking for is dealt with in part 4, but I would recommend you read all 4 parts. There is a link to the next article at the end of each one.

Best of luck to you!

10:34 p.m. on September 8, 2009 (EDT)
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If I'm not badly mistaken the Sweetwater chemical treatment is chlorine dioxide.

Yes you are correct Trout or that's what my bottle states the active ingredient's are.

I carry a bottle with my gear as a backup and I use it in conjunction with my mechanical filter if the water is questionable or really nasty.

11:15 p.m. on September 8, 2009 (EDT)
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Thanks for the replies. I will definately read the article by Bill. However, my sweetwater chemical solution states that its active ingredient is sodium hypochlorite, ie., bleach. I've read somewhere that you can treat water with bleach, but I'm not sure if its suitable without some sort of mechanical filtering first, as would be chlorine dioxide/iodine. Maybe MSR changed their solution recently, I just bought the filter a few weeks ago.

3:19 p.m. on September 9, 2009 (EDT)
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Here is a link you may want to read it will give you a rule of thumb giude to emergency water treatment.

But still read Bills post on water treatment it is very informative and accurate.

3:39 p.m. on September 9, 2009 (EDT)
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Or just choose your watering holes wisely, don't treat and hope for the best.

3:48 p.m. on September 9, 2009 (EDT)
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Aaa this is true grimstuff, but I have been places where that is impossible. Like some of the areas of the ADK that are riddled with beaver dams, even the streams back up and don't move very fast because of the beaver dams raise the water table in that area.

8:48 a.m. on September 10, 2009 (EDT)
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I carry some Micropur tablets in my first aid kit as a backup. With the foil packaging and all, they wear well and are light. Haven't used them yet except to experiment with.

11:15 a.m. on September 10, 2009 (EDT)
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An emergency backup that is partly effective is UV radiation from plain old sunlight. This is discussed in Paul Auerbach's Wilderness Medicine book. It isn't guaranteed, but if all else is lost, vanishes, the tablets got wet, or otherwise unavailable, filtering the large chunks out with a T-shirt or coffee filter, then leaving a transparent container of water in direct sunlight for a number of hours will kill off at least part of the critters. It's a really last-ditch, desperate attempt and best done at high altitudes. Doesn't work well in heavy fog or in the jungle where there's no sunlight.

11:30 a.m. on September 10, 2009 (EDT)
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Bill, I think that's the basic premise behind drinking from high alpine lakes--the UV zaps the upper part of the lake and the cysts (if any) naturally fall to the bottom. Of course, I wouldn't drink from lakes that people use to swim or camp around... common sense will get you pretty far. I guess we're lucky to have the high sierra where there are still pristine areas. Can't say much for anywhere else, since this is the only area i've done any backpacking.

I don't know if this has ever been posted on Trailspace (I did a search for the author's name), but this is a pretty informative article on the likelihood of getting Giardia in the Sierras:

6:36 p.m. on September 10, 2009 (EDT)
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Thanks for all the info guys. I remember reading a while back (I think on this forum) a debate about whether to buy more sweetwater solution when one runs out. Now that I know its basically less concentrated clorox, I'll just buy it at the grocery store and have enough forever at a 100th of the cost. However, if it can really be that simple and easy, why are people paying for the iodione/chlorine dioxide???

1:35 p.m. on September 19, 2009 (EDT)
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McGee55: To answer your question: why are people paying for the iodine/chlorine?

If you use chlorine in water that has organic material in it, you get a ugly byproduct: trihalomethanes-----which can cause cancer.

Here’s a link to an E.P.A page on the subject:

Your Sweetwater system is safe, since the microfilter takes out organic material, but direct treatment with chlorine is not recommended.

Chlorine Dioxide tablets don’t produce trihalomethanes. The three brands: Micropur, Potable Aqua Chlorine Dioxide Tablets, Aquamira Chlorine Dioxide tablets, are all identical and are E.P.A. approved.

Re Iodine tablets: here is a link to a U. of Arizona study on effectiveness of Iodine tablets on Cryptosporidium.

This statement sums up the U of A. testing: “These data strongly suggest that iodine disinfection is not effective in inactivating Cryptosporidium oocysts in water. Because this organism is common in all surface waters, it is recommended that another method of treatment be used before ingestion.”

Cryptosporidium protozoa are just as common as Giardia, cause about the same symptoms, and are real tough to kill with chemical: hence the 4 hour treatment time with chlorine dioxide.

8:06 p.m. on September 19, 2009 (EDT)
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riverridgeway touches on an interesting point. When we were living in Mississippi, it was noted that cities along the lower part of the Mississippi River that used river water (most notably Baton Rouge and New Orleans, being the two largest cities) have significantly higher rates of certain cancers (mostly in the GI tract). This was traced to the presence of trihalomethanes resulting from the massive doses of chlorine used for water treatment reacting with industrial and agricultural runoff. Agricultural pesticides and fertilizers turned out to be the main culprits, with natural occurring organics having a very low resulting trihalomethanes. The general consensus in the wilderness medicine community is that this is not a serious concern for backcountry users, especially at high altitudes. You should do at least settling/decanting and coarse filtering (coffee filter or bandana), since disinfecting with halogens is significantly slowed in the presence of a major amount of organics (like algae) and sediment like glacial flour or volcanic ash, and fllters, whether pump or gravity feed, clog quickly with such material ( a good reason to use a field-serviceable filter). Note that certain algaes produce toxins that are not removed by filtering or by use of halogens, though you generally won't encounter these in alpine water sources.

The problem with halogens (particularly bleach) is not that they do not inactivate or kill crypto or giardia, but rather that they are so sensitive to temperature (remember your high school chemistry - reaction rates slow at low temperatures), so that the required time is impractical for the backpacker at altitude using water from a cold stream. ClO2 takes 4 hours or more for crypto and giardia at "room temperature", and significantly longer for the cold water many of us encounter in early spring, late fall, and all year in the high Sierra, Cascades, and Rockies.

However, iodine and chlorine (both bleach and ClO2) work quite well for viruses, which are becoming increasingly common, especially considering that very few of the backpacker filters have a fine enough pore size to filter out some of the more dangerous viruses. Thus the advice you often see for first filtering, then adding a halogen (some filters have an iodine resin through which the filtered water passes, which gets most of the effect with a much reduced probability of iodine side effects - avoid even the iodine resin matrix filters if you have thyroid problems).

All this talk about purifying the water (aside from the confusion generated by the terms "purify", "filter", "sterilize", and "potable") makes it sound like you should take all your water in bottles you bought at the store, and that you are in imminent danger of dying out there from just a sip of stream or lake water. The truth of the matter is that the problem is overstated. Yes, there are critters and poisonous chemicals in the water. But most of the time, the concentration is so low and the exposure so brief that you will not get sick from drinking from streams and lakes in the hills IF you use a little common sense. You are far more likely to get sick from poor sanitation (preventable by simple hand washing or using hand sanitizer) from yourself or your companions who did the food preparation. I, along with the vast majority of people I spend time in the wilderness with, have rarely if ever gotten sick from mountain water, using good sanitation practices, a bit of judgment in selecting water sources, and some means of treatment - filtering, halogens, UV, or just being choosy about what stream we dip our cups in. The very few times I ever got sick from food or water were in civilization - a shrimp cocktail served in First Class on a commercial airline flight (6 of us traveling together all got sick with the only thing in common being the shrimp cocktail - someone else was paying for the tickets), another time in a catered banquet for my professional organization, a couple times that I made the mistake of going to a fancy 4-star restaurant - never had a problem with street food in 3rd world countries. Does this say I should never eat in fancy places?

9:13 p.m. on September 20, 2009 (EDT)
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Or just choose your watering holes wisely, don't treat and hope for the best.

Have you ever suffered the wrath of the little bugs?I have and it is not fun on any level.Guess work is not the way to go.ymmv

10:15 p.m. on September 20, 2009 (EDT)
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A lot of good information for me here guys, thanks. It now makes sense to me why the filter instructions say that I can drink the water a mere 10 minutes after treating it with the bleach, because it is really only intended for viruses (I previously believed it was also intended for whatever critters that make it past the filter). This, however, leaves me in my original quandary of deciding which is the most efficient method of backup filtration should something unfortunate happen to my filter. I don't imagine coffee filters are fine enough to deal with giardia/crypto. Perhaps I'll just plan to boil after running it through a coffee filter. Its probably obvious that I'm looking for alternatives that are cheap and non-mechanical, ie., cannot break.

Also, Bill, I read on several websites that the amount of bleach necessary to effectively treat giardia or crypto renders the water unsafe for human consumption (see below). Whats your take?

"Bleach does not work well in killing off Giardia or beaver fever or Cryptosporidium parasites. The amount of bleach needed to kill these parasites makes the water almost impossible to drink."

11:40 a.m. on September 21, 2009 (EDT)
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I previously believed it was also intended for whatever critters that make it past the filter

Well, viruses are critters.

On the "amount of bleach" statement - the effectiveness of any chemical treatment is dependent on a number of factors, making a thorough discussion "difficult to comprehend" in a single gulp. Temperature is a factor. pH is a factor. Concentration of the chemical is a factor. Time allowed is a factor. And more. Keep in mind that the most commonly used treatment in municipal water supplies in the US is chlorine in one of several forms. Swimming pool treatment is most often chlorine in one of several forms. (swimming pool treatment at the start of the season and periodically thereafter is called "shock treatment" because of the huge amount of chlorine added - I suspect you don't like drinking swimming pool water, even accidentally).

The link you give is basically correct, but a bit overstated. Note that the comment about the huge amount of bleach needed is in reference to heavily contaminated water, such as you would find in urban disasters, not what you more commonly encounter in wilderness situations. The source is Canadian, and in the Rockies and BC Ranges, the water at anything more than a couple miles from the trailhead has a pretty low concentration of nasty critters (just avoid beaver ponds).

Some people do not like even a slight chlorine taste (me for one). That's why I often just boil the water for drinking, at least on short, weekend length trips - costs a lot of extra fuel, but at least I don't get chlorine or iodine taste.

On the coffee filters - I have never tested coffee filters with water saturated with crypto or giardia, just used them to remove silt, sand, twigs, and such. However, a couple of friends who are MDs in the Wilderness medicine field tell me that at least some coffee filters are fine enough pore size to remove crypto, which are pretty large as are their oocysts. There are articles in the professional wilderness medicine journals to this effect. I would post the references, except we are still in the midst of moving into our new house and starting to unpack.

Your original question was about "Backup Water Treatment" and a lot of the discussion has been about emergencies where you somehow lost or broke your filter, the halogen pills got wet or lost, and maybe you didn't have fuel for your stove. To summarize the answers for such emergencies (emphasize - this is wilderness we are talking about, not areas where you have urban, industrial, and agricultural pollution, nor a disaster where municipal supplies are compromised or in 3rd world countries), you can get some distance toward potability (not sterile or pure in the technical sense) by using coffee filters, a T-shirt folded several times, "sun sterilization", and mostly judicious choice of source (e.g., avoid beaver ponds and scummy mudholes). In most high altitude locations where you might backpack, judicious choice will lower the probability of getting crypto or giardia. If you do get into such a situation, imbibing enough water to get you sick still allows about a week between drinking the water and the symptoms. So head out right away and talk to your doctor. Again, this was the emergency situation where you lost all other means of treating your water.

For the urban or 3rd world situation, I would say that carrying multiple backups and just putting up with the chlorine or iodine taste, combined with as judicious choice of water source is the way to go. For disaster preparation (hurricanes, floods, earthquakes), prepare your kit well ahead of time, including multiple alternatives stored in "grab kits" and several places (couple around the house, plus in each car in the family). Having lived in hurricane country (and been through one plus close to several tornados) and living now in earthquake country (been through one big one) plus urban wildfire country (only thing there is flee well ahead of the fire - don't even think about trying to save the house), just be very well prepared for the full range of eventualities.

1:03 p.m. on September 21, 2009 (EDT)
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Excellent. I'm a firm believer in Murphey's Law, so I try to reasonably prepare for most feasible potentialities. Thanks again to everybody for their suggestions/info.

8:42 p.m. on September 21, 2009 (EDT)
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I haven't been following the news, since we are moving into the new house and just got the TV connection set up. So I hadn't realized how timely my comments about urban disasters was, until I listened to the radio news about the flooding in Georgia.

10:30 a.m. on September 23, 2009 (EDT)
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Aqua Mira tablets.

9:37 p.m. on September 24, 2009 (EDT)
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I just want to say that Iodine, Chlorine Dioxide, Micropur MP 1, and other tablets as well as solutions including MSR Moxie all take 4 hours to kill Cryptosporidium it may work faster if the water is warm, out of a stream or lake its 4 hours. The above items work fast for Viruses about 10 to 15 minutes. If your filter breaks all the above work well including boiling if you have extra fuel. I use the adventure Steripen for three years with no problems, it is so impressive everyone I pack with has gotten one. We all take the pen when we go and have at least 2 of them and have never had one fail.

A friend used the pen out of country for five weeks and was the only person in her group except for her guide that did not get sick??

10:31 p.m. on September 28, 2009 (EDT)
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I wish I could afford a steri pen. Its funny, I was just out this weekend and ended up sharing a shelter with a guy whose filter busted on him on his previous trip. I keep asking myself - Why do they have to make those things out of cheap plastic?

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