Wednesday, March 11, 2009

Lightweight Water Treatment Options

One backpacking topic I’ve spent a lot of time thinking about (and researching) was water – how to get it and how to make sure it won’t make me sick. For the most part, American’s are quite ignorant about water concerns because they can find fresh water nearly everywhere during our daily activities. We completely take this luxury for granted and it doesn’t become even the slightest concern until we travel outside of our borders or attempt to take water from a source that isn’t a faucet or a hose. If you ask most Americans, they will tell you to stay away from the water in Mexico as it has become somewhat a lore involving tales of unsuspecting vacationers who fall ill for several days after even merely dipping their toothbrush into tainted water. The reality is, much of the world doesn’t have the luxury of clean tap water and Mexico isn’t in the minority. A few months ago I was in Germany and was shocked to learn that a civilized society such as Germany required that I drink bottled water at every turn. Truth be told, I drank water from the faucet at my hotel before knowing I shouldn’t. I didn’t get sick, but I was warned it just wasn’t very good for me. Trust me, when you are in unfamiliar surroundings and you can’t drink water from your usual sources, YOU NOTICE IT! Backpacking is no different with the exception that most water sources are ponds, streams, springs, glacial melt, ice, snow, etc.

The quality of water in the backcountry is affected by numerous factors which can include temperature, turbidity, animal activity, chemical runoff from businesses or animal fields, runoff from chemically treated roadways, human activity, etc. Mere appearances can only go so far to help you determine which water sources are safe and which aren’t. Therefore, it is a smart decision to treat ALL water when in the backcountry. Although it may seem like overkill to treat 100% of backcountry water, for me it makes logical sense as I have no urge whatsoever to deal with stomach cramps, nausea, weakness, bloating, diarrhea, or vomiting. Often cutting a trip short or seeking medical treatment isn’t really an option, so the responsible choice is to treat everything.

Before treating, it is important to do your best to select safe water sources. Avoid sources with high animal activity or areas impacted by humans. Try to uses water sources which are still and clear as this will allow many microorganisms to sink. Turbulent water may otherwise keep them suspended. Get water from as close to its source as possible, or at the very least, as high upstream as reasonable. If your only options are snow or ice, choose ice. Ice has greater water content. Obviously, stay away from any discolored snow. Practice good hygiene. This includes using only TREATED water for cleaning anything that comes in contact with food, to include food, and even something as simple as your toothbrush. Wash your hands frequently and use soap. If water is bubbly, discolored, smelly, or if you see anything dead around it - stay away from it.

To fully appreciate how to properly treat water, you need to know what the threats are and how to mitigate those threats. Without playing the role of Mr. Science, there are essentially four threats in most water sources which I’ve identified below. So you can fully appreciate how small these items are, you need to understand the term “micron”. A micron is not visible to the human eye and is 1 millionth of a meter, or .0000394 of an inch. A period at the end of a sentence is roughly 500 microns. The unaided human eye cannot see anything smaller than 50 microns. The straining ability of the pores in filters and purifiers is typically measured in microns. Often you will hear friends and salespeople recommend that you seek out a "0.2-micron" filter. Why is this important? Well, one of the most popular filter pumps is the Katadyn Hiker. Guess what, it filters at 0.3-microns. Worried? Maybe you should be...

1) PROTOZOAN CYSTS – These are hard shelled, single-cell parasites which include Giardia and Lamblia and range in size from 5 to 15 microns. This also includes Cryptosporidium Parvum which is 2 to 5 microns in size. Giardia occurs in the small intestine where cysts hatch and give you diarrhea, gas, nausea, and/or cramps and symptoms appear within 1 to 2 weeks and can last 4-6 weeks or longer. Those with weakened immune systems could be more heavily impacted. Cryptosporidium can give you similar symptoms and can also include loose stool, cramps, slight fever, and an upset stomach. These systems generally appear in 2 to 10 days and typically last 2 weeks. Animals and humans carry Protozoa.

2) BACTERIA – Bacteria are smaller organisms which can include E. Coli, Salmonella, Cholera, and Campylobacter Jejuni. They range from .2 to 10 microns and symptoms include diarrhea with appears within 6 hours or 3 to 5 days and last 4 days or longer. Animals and humans carry Bacteria.

3) VIRUSES – Viruses represent the tiniest of organisms ranging from .004 to .1 microns. They include Hepatitis A, Rotavirus, Norwalk Virus, and even Polio. Although these are the least commonly found pathogens in the wilderness water sources, they represent often the most harmful. If you were wondering, most waterborne viruses which affect humans in the backcountry come from human fecal matter.

4) CHEMICALS AND RUNOFF – As the name implies, another water-nasty includes agricultural runoff (herbicides, pesticides, etc.) and industrial runoff (metals, mine tailings, etc.).

So how do you treat for these things? Well, there are many ways which include boiling, iodine, chlorine, bleach, UV light, carbon filters, and physical filters, but here are a couple things to consider. First, Cryptosporidium Parvum is highly resistant to iodine and chlorine. Filters and purifiers work well to treat bacteria. Viruses can slip through most filters. Carbon filters do well against a water source tainted by chemicals or toxins. Based on the micron size of the water-nasties indicated above, a pump filter would need to be able to be able to filter out a micron of .2 or smaller to be effective.

If you read this correctly, it sure seems like there are a lot of ways to treat water but many aren’t effective for everything. There is also a difference between a filter and a purifier. Although both treat microbiological aspects of tainted water, only a filter removes Protozoa and Bacteria while a purifier does this and eliminates Viruses too. Below is what works, what doesn’t, and some limitations:

First, boiling water is 100% effective against Protozoan Cysts and non-toxic Bacteria and Viruses. The U.S. Environmental Protection Agency (EPA) recommends bringing water to a rolling boil for one minute to kill microorganisms. At elevations higher than 6,500 feet, the EPA recommends boiling times to be extended to 3 minutes. The problem with boiling is that it is time consuming, requires a lot of fuel, requires appropriate containers to boil water, and it does not remove any sediment.

Physical filters force water through a porous internal element housed within a filtering unit. As long as the internal porous element is able to stop microns .2 and smaller, it is a very effective option to treat taint water. They are also the best method to filter out sediment, but can get clogged because of the sediment. Unfortunately, pumps are expensive, heavy, require a lot of effort, and require maintenance. I have known many people who intended to use a pump filter for their entire thru-hike just to have it break 2 weeks into it. Pumps are also ineffective in winter because the pump itself freezes or otherwise can’t process the icy water. Gravity-fed systems take away the need to physically pump, but make the process a little more cumbersome because it requires more parts (one bag drips through a hose filter into another bag, but both can’t hold water at the same time which means you have to carry an extra bag and hose for no reason).

A recent effective water treatment is to use an ultraviolet light to treat tainted water. This is the same processes used for decades by commercial bottling plants and commercial water systems. It works by damaging the DNA of microbes, even viruses, causing them to be unable to reproduce and cause harm. These devices exceed the EPA standard for water purifiers by killing Bacteria, Viruses and Protozoa. Unfortunately, they only do well in water that is already clean which generally means a pre-filter is needed. This is also a costly item which requires batteries and quite a bit of care to ensure it isn’t accidentally broken. It is also ineffective against larger volumes of water as most units are designed only for exactly 1 liter.

Exposing water to halogens such as iodine or chlorine is believed to kill Bacteria and Viruses, especially in greater doses. Unfortunately, it does not kill all Protozoan Cysts or Cryptosporidium Parvum because of their harder outer shell. Chemical treatment effectiveness also depends a lot on the initial quality of the water. Sediment will remain in water and cold water can take 4 hours or longer to get the full effectiveness of the treatment. In many cases, however, especially with clean water at 50 degrees or above, water can be treated in less than an hour (even 30 minutes) quite effectively. Chemical treatments represent one of the lightest water treatment options. Because there are different chemical treatment options, I felt it was appropriate to identify them below:

Water treated with Iodine tends to leave water tasting funny and doesn’t clear up any discoloration. It may also be unhealthy for some people, especially pregnant women, individuals with thyroid conditions, people with weakened immune systems, or people who use it for longer than 2 weeks. Iodine must be kept in the manufacturer’s bottle, usually a small brown glass jar with a screw-on cap, as exposure to the elements and light can damage its effectiveness. A couple other downsides of using iodine is that the water stays dirty and that some effectiveness is lost in cold or murky water. I should also mention that it doesn’t taste very nice and also does not kill cryptosporidium.

Aqua Mira is a chlorine dioxide and typically comes in two separate bottles which must be mixed together, then wait for five minutes, then added to water. It has no taste which is preferable by many. It kills cryptosporidium, which is an advantage over Iodine. Micropur, another chlorine dioxide identified below, is actually a little stronger and is therefore effective with other concerns.

Worth noting about chlorine dioxide technologies is that they are more effective than Iodine and Chlorine for reducing the pathogenicity of water containing bacteria and Cysts because it better penetrates microbial biofilms attached to soil particles which otherwise harbor large quantities of pathogenic microorganisms. For waters which are known to be tainted or are physically dirty, higher dosages and longer waiting times are encouraged.

Micropur is nearly the same as Aqua Mira (above) with exception to the fact that it comes in a higher dosage. It is thereby effective against bacteria, protozoa, and viruses but has the same limitations in dirty or cold water.

If you want to deal with a water treatment which I wouldn’t touch because of my personal fear of making a mistake, it is treating the water with household bleach. Bleach should be 4-6% sodium hypochlorite and soap-free. The standard treatment is to add four drops of bleach (sodium hypochlorite) per quart and let stand for 30 minutes before drinking. Bleach treatment can impart an unpleasant taste to water and incorrect measurements can cause serious medical harm.

If you really wanted to be puckered, you could filter your water, treat it chemically, treat it with UV light, and then boil it. This is very impractical, however. It is worth mentioning that you aren’t likely to be exposed to many (or any) of these potential concerns, but you need to plan for the bulk of whatever concern is evident in the environment you’ll be visiting.

Many experts claim combining a chemical treatment with filtration is a very solid option for treating water, but is this a good choice for the lightweight backpacker? The answer is yes and this option and others could be very effective. Personally, I use Micropur tablets ( most of the time without any additional treatment discussed herein as they are the lightest option and very effective. I've also used the Aqua Mira liquid drops and tablets in the past, but I've evolved to the Micropur because they are essentially the same thing with more killing power. If I know I’m going to a place with particularly questionable water, I add a AquaMira Frontier Pro filter ( Although I've used a pump and gravity filter in the past, I don't use them anymore as I simply don't feel their weight and mechanics are worth it. Regardless of what treatment choice I use, I always prefilter the water with a small piece of nylon which essentially blocks larger sediment from getting into my water container. The nylon bag I use is actually intended for use as table settings which I picked up from Walmart. Aside from working as a nearly zero weight prefilter, it also holds whatever water treatment option I'm using quite nicely. When I travel I have been known to use a UV Pen such as the SteriPen Adventurer ( It works fine and it is very convenient, but I just think it is too mechanical and heavy to take backpacking. At one time I also attempted to utilize a direct inline filter such as those sold by Sawyer ( The filter turned out to be costly, clumsy, heavy, and generally irritating to use. At this point, I’m very happy with my water treatment choice and I have yet to have any problems in the backcountry. One thing I should mention is that absolutely no treatment solution is going to do you any good if you leave tainted water around the threads and mouth of your water container. If it isn't all treated, it could possibly harm you. Obviously it is tough to treat every last drop all over the container, so make sure you clean off any areas that you'll be touching (especially with your mouth).

Choosing the right water treatment options depends on the water source and preference of the user. For me, I have found an effective and lightweight water treatment which is far more useful and desirable to me than any heavy and expensive mechanical filter.


Anonymous said...

A few months ago I was in Germany and was shocked to learn that a civilized society such as Germany required that I drink bottled water at every turn. Truth be told, I drank water from the faucet at my hotel before knowing I shouldn’t. I didn’t get sick, but I was warned it just wasn’t very good for me.

Your statement is not correct. Tap water is safe throughout Germany. Germans drink bottled water out of habit.

Here is a post from someone on the topic:

Tap water IS safe everywhere in Germany. Actually, the quality standards for tap water ("Leitungswasser") are higher than those for bottled water ("Mineralwasser"). Some brands of "Mineralwasser" have contents of sodium, nitrite, or even arsenic that would be unacceptable for tap water. Furthermore, the quality of tap water is checked at least daily by the authorities. This is not true for bottled water.

However, it is true that virtually nobody drinks tap water in Germany. Why? Maybe because many Germans do not know how good their "Leitungswasser" is. Others drink bottled water because they prefer carbonated water. Finally, in some places tap water can contain chlorine or iron. This doesn't affect the safety, but it can cause an unpleasant taste.

You can of course order tap water in a restaurant, but unless the waiter is familiar with American habits he might think you are just too cheap to buy a "real" drink.
Hannover, Germany 01/31/00

Jolly Green Giant said...

Thanks for your detailed response Jochen. I think you hit the nail on the head that there may be a misperception because I was told tap water should be avoided by both Germans and non-Germans. I'm glad you cleared up the misconception. Thanks.