Drinking Water for Hiking: Myths and Facts

Myths about contaminated water
– There are several references to the Mueser book, which is not a scientific paper, but written by a hiker. Maybe he has appropriate references in his book to back up what he is stating.
– You certainly don't have to be a thru-hiker to have symptomatic Giardiasis when it has an AVERAGE incubation period of 7 days. I see you changed your paper to reflect that.
– Prophylactic treatment would occur before symptoms of an infection as a measure of prevention. Giving meds to a symptomatic patient before a definitive diagnosis would be called emperic treatment.
– It's not a myth that backpackers get sick from Giardia in the water, because they can. If even one case has been proven, it is not a myth.
– I don't think iodine should be recommended to anyone. Chlorine bleach is better, to me, for the similar purpose.
– No one should rely only on a battery operated UV system if in the backcountry.
– The time to boil water does seem to be a bit controversial and differs from disaster scenes to dayhikes. A simple rolling boil would be my goal.

Chlorine bleach has a bit of a problem depending on the water quality. If there is a lot of decaying plant matter like leaves, nitrogen gets into the water, and the chlorine bleach can form chloramines. Bleach is still better than nothing, but its efficacy varies widely.

Iodine does not have that same weakness, but it has other weaknesses. More people can get sick from a dose of iodine.

–B.G.–

Hey, Buck,

I agree that the quality of discussion in this thread has been amazingly good. Is this really the internet?? Can't someone please use the word "Nazi," or make an ad hominem argument? :-)

Buck wrote:
"The Rockwell paper quotes an article that says 'the risk of contracting giardiasis in the wilderness is similar to that of a shark attack' That doesn't square with Welch 'Published reports of confirmed giardiasis among outdoor recreationalists clearly demonstrate a high incidence among this population.' Both scientific reports. At least Welch's is. Rockwell uses a little too much anecdotal evidence."
These do appear to contradict each other, but here's the thing. If you look at the Rockwell quote in context, I think he's talking about the risk of getting a giardia infection from drinking backcountry water. But Welch is talking about the total risk of getting giardia, i.e., including all possible routes of infection. As far as I can tell from the scientific evidence, the risk of getting giardia while backpacking is frighteningly high — almost as high as what you get by putting your kid in daycare — but the route of transmission is primarily that you get it from your hiking partner, who didn't wash his hands well enough after pooping and then handled the pot where you cooked your ramen.

Ben

Dr Seifert (MSU- that's Montana State University :)) has conducted a few studies on the effects of dehydration on skiers, he found a pretty strong correlation between performance and hydration level (or lack thereof)

while it's probably true some might be drinking (and carrying) too much water while hiking, seems to me better to err a little on the too much side, than too little

John wrote:
"There are several references to the Mueser book, which is not a scientific paper, but written by a hiker. Maybe he has appropriate references in his book to back up what he is stating."
This is a valid point. What I would say is that the Mueser book is scientific, but is not a peer-reviewed scientific paper. My article includes a variety of evidence, ranging in quality from peer-reviewed scientific papers to purely anecdotal evidence (on reliability of steripens). Caveat lector. I think the Mueser book is more valuable than anecdotal evidence, less valuable than a peer-reviewed scientific paper — but it gets at issues that AFAICT no peer-reviewed scientific paper has gotten at.

"It's not a myth that backpackers get sick from Giardia in the water, because they can. If even one case has been proven, it is not a myth."
OK, this is probably going to come off as overly argumentative, but here goes. *Is* there a single proven case of a backpacker getting sick from drinking backcountry water? First off, I guess this person would have to have been hiking solo, because otherwise we'd have no way of knowing whether he got it from his hiking partner's p**p [BPL's profanity filter doesn't like p**p]. Also, he'd have to have been hiking for several months without eating at a restaurant, because in some cases the incubation period for giardia is several months. He'd have to have been diagnosed with giardia based on tests on a stool sample. This gets pretty difficult. Most through-hikers pass through a town at least once a month or so, and you'd better believe that they head for the salad bar. Giardia is an extremely common ailment in the US. Tests show that the incidence of giardia among kids at daycare centers can be 90%. Since it's an extremely common ailment, how do you prove that a particular backpacker got it from drinking backcountry water and not from some other route?

"No one should rely only on a battery operated UV system if in the backcountry."
Why? Batteries operate according to the laws of physics. They don't just randomly fail. I do prefer not to rely on electronic gadgets for my safety, but IMO this is too strong a blanket statement.

"Chlorine bleach has a bit of a problem depending on the water quality. If there is a lot of decaying plant matter like leaves, nitrogen gets into the water, and the chlorine bleach can form chloramines. Bleach is still better than nothing, but its efficacy varies widely."

Bob, can you amplify more on this? I understand that, e.g., in swimming pools it's chloramines that cause eye and skin irritation, not chlorine. But is this really a realistic issue with (non-emergency) drinking water? Is the issue only one of taste, or can the chloramines actually make you sick or something…?

If you had fairly clear water, then you can add the correct dose of chlorine and expect to kill various "bugs" in time. However, if there is a lot of nitrogen in the water, much of the added chlorine gets bound up making chloramines, and therefore there isn't so much chlorine to work on bugs.

Unfortunately, a backpacker can't look at water and tell that there is nitrogen in the water, so the backpacker can't tell how strong of a chlorine dose is necessary to get the job done.

So, the issue has nothing at all to do with taste.

–B.G.–

I had acute Giardiasis for two weeks on my PCT thru hike. It was clinically diagnosed by a doctor at Stateline medical center in South Lake Tahoe. There are very specific symptoms that come with acute cases of giardiasis that are unique.
I am posting the following to help future hikers so they don't suffer as long as I did and hopefully get treated before they lose 30lbs in 20 days like me.
Giardiasis First Symptoms:
Loss of appetite, muscle weakness, lethargy, gas.
Later:
diarrhea, abdominal cramps, sulpher smelling belches and gas, with greasy stools
Acute stage:
Weight loss, dehydration, extreme abdominal cramping that comes and goes several times and hour, mucousal diarrhea many times an hour even in sleep with copious quantities of clear mucous or with undigested food present, complete loss of appetite, extreme fatigue, headache.
I had hiked from Crabtree meadows to Echo Lake before i sought treatment. I kept thinking I could wait it out. I even stopped eating for a couple of days on trail to try and clear out my gut. By the time I shambled in to Echo lake my shoulder bones and ribs were clearly sticking out of my skin.
The treatment consisted of 250mg of metronidazole (generic for Flagyl) three times a day for 7 days.
I spent two days in South lake tahoe on metronidazole before hiking on. By day three my appetite had recovered and i felt much stronger. By day 4 my stool returned to normal. By the time i reached Donner Pass I was almost completely recovered and able to eat 10,000 calories of food at a single sitting at the Soda Springs store.
The most difficult part of the whole experience was finding safe places to pass diarrhea. I walked many miles doubled over in pain to get as far away from water as possible.
Whether you believe it is Giardia or not if you are a thru hiker that suddenly has lost their appetite it's NOT normal! If this then progresses to diarrhea and continues for a week, don't wait, get help.
Every year many thru hikers get sick. I wont speculate whether it is in the food, water, or by their own hand but the fact remains hikers get sick on the PCT between Walker Pass and the Sierra in particular every year.
I read the above article and although it is well written it is also based on anecdotal evidence.
The fact is: Hikers get sick every year on the PCT and some are taken off trail by that illness. Articles that use anecdote or cherry pick scientific evidence are dangerous to hikers. Hikers being "overprepared" by treating their water does no harm.
I really don't understand the motive behind the article. It ignores the reality of what is happening on the trail today. Those references are ancient history.
So lets assume it is correct.. that there is no reason to worry about the safety of back country water.. that all the illnesses on trail are due to poor hygene and lack of hand washing. Then why is it many hiker illnesses occur in a cluster between Walker Pass and the Sierra at different times of year? This is reality today.
I consider the hikers I met and the hikers of past years that all got sick within 10 days of being in this area to be enough anecdotal evidence to advise caution.
I don't want to be right or wrong about whether there is Giardia in sufficient quantity in the water on the PCT to make hikers sick.
I am saying why not expend energy collecting fresh evidence? Why not go to Kennedy Meadows and take swabs of thru hikers hands and test them for Giardia spores? Why not take fresh samples of water sources on the PCT? Merely quoting a passage in a book that says there were .3 spores per liter is irrelevant because the sample size is too small. Science is hard work. Science takes money and time and it's far easier to rely on anecdote or rephrase the passages of a fory year old book than do real science.
None of that changes the fact that something is sickening hikers every year. Until real science is done noby has the answer regardless of how they argue the case.
I just want to let hikers know the symptoms of acute Giardiasis and also that it does not neccesarily take you off trail.
If you have been suffering with acute Giardiasis and manage to eat some macaroni and cheese only to see it come out the other end the same color and consistency as it went in you know it has completely colonized your small intestine.

Ben, I think you are getting carried away with the proof or non-proof of Giardia.

A bunch of us went backpacking, including a close friend who was completely healthy beforehand. When we got to the lake, some went swimming, and some did not. I stood there and watched as some of the swimmers were spitting lake water at one another, and I thought that was particularly dumb. Some consumed drops of the lake water.

Five days later, the close friend had some initial mild symptoms, and then they got worse. By the ninth or tenth day, a doctor's appointment and lab tests proved that the friend can contracted giardiasis. Logic dictates that it came from the lake water. I didn't know it at the time, but later on some of the other swimmers reported to me that they had similar episodes over similar time periods with similar symptoms. Lab tests proved giardiasis there, to different degrees. None of the non-swimmers got sick.

So, there is no doubt in my mind that backpackers can contract giardiasis from backcountry water. In isolated pockets like my lake with my friends, it seems to hit pretty thoroughly. That had nothing to do with food, because the entire group ate the same central commissary food out of the same cook pots.

Wisdom dictates that we should all be taking some precautions to avoid contaminated water. The extent of the precautions depends on many variables, though.

–B.G.—

*Is* there a single proven case of a backpacker getting sick from drinking backcountry water?

"Nineteen of these [Giardia] outbreaks were attributed to consumption of contaminated drinking water; only two outbreaks were reported among individuals identified
as campers or backpackers." http://download.journals.elsevierhealth.com/pdfs/journals/1080-6032/PIIS1080603295710468.pdf

That's from Dr. Welch himself from one of the originally cited articles. It's not a myth. The only debate is the level of risk.

increased risks have been found in populations where surface water sources are not filtered, persons who use shallow well water systems, persons who drink contaminated water while picnicking, camping, and hiking (EPA) http://water.epa.gov/action/advisories/drinking/upload/2009_02_03_criteria_humanhealth_microbial_giardiafs.pdf

Here's a great article summing up the opinions of several experts: http://www.rei.com/expertadvice/articles/water+risks.html

I cherry picked this part: Auerbach recalls caring for one backpacker who drank straight from a stream while on a trip in Montana. "He hiked another 400 yards and there was a cow in the water," he says. "He was rewarded with a classic case of giardiasis."

One of the "giardia skeptics," if you will, is Dr. Robert Derlet. Likely smarter and better educated than me, but he says I'd say there is less than a 1 in 100 chance that a person would get sick drinking untreated water from side streams. By side streams, I mean a stream that has no upstream trail, no human presence and no grazing animals. On trails, how often do we encounter that? Maybe never? He also says The biggest trend is what's obvious: In watersheds where cattle have grazed, the water is contaminated…Giardia-infected cattle excrete nearly 100 million Giardia cysts per day It takes about 10 or more to get sick. Last summer I drank untreated water from a beautiful, clear, swift-flowing stream where I discovered, a few steps too late, that cattle had been stomping around. I got sick a few days later and was later diagnosed with Giardia. Positive link? Nope. But I will happily treat all backcountry water for the rest of my life to avoid the next case.

Amended to add that it was in the Giardia Zone that Ice Axe identified where I got sick, as have many others.

"But I will happily treat all backcountry water for the rest of my life to avoid the next case."

Yes, I certainly feel the same way. I have had it, and it has gone away. Not really dibilitating, but, I didn't want to be far from a bathroom from three days. This was long ago…well over 50 years…

The point is that a large segment of the population is asymptomatic or only mildly effected. Do you know where you stand? Once you have had it, what are the chances of reinfection? What of the rural population that drink from untreated wells every day? Spring boxes can be real bad, yet, these people never get sick. Aquired immunity?

Yes, side waters are safest. This is where I sometimes drink. But, there was no paths and few animals in the area. Cold, clear, spring fed, running water, no different that what I have been drinking, probably a whole lot better.

That said, do I recommend treating water? Treatment is always recommended. Most hikers live in urban environments. Water is typically piped into their homes from some common source and it is treated. Chances are, they are highly suseptable to gardia. For an old farm boy, I can get away with drinking large amounts of gardia in my water. I am not immune, but, there is a level of tollerance. How much, I don't know. What is the mechanism? Why does it not seem to bother me as much as others? No answers, sorry. Just these and more questions….

What is the area like between Walker Pass and the Sierra? Alpine wilderness? Meadows used for cattle grazing?

Matt (iceaxe) I appreciate your detailed description of symptoms, helpful.

One thing is, that if your UV rarely breaks, drinking unfiltered water could be an acceptable backup. Rejecting UV because it's electronic and thus susceptible to failure may be over-reacting.

For anyone with a history of getting Giardiasis, I can see being more careful.

Hi, Buck,

'"Nineteen of these [Giardia] outbreaks were attributed to consumption of contaminated drinking water; only two outbreaks were reported among individuals identified
as campers or backpackers." http://download.journals.elsevierhealth.com/pdfs/journals/1080-6032/PIIS1080603295710468.pdf '
This is from the abstract of Welch 1995, which is one of the papers I referenced in the article. You've taken a sentence out of the middle of the abstract, and I think this lack of the proper context makes it easy to misinterpret what it says. The conclusion stated at the end of the abstract is that the data "…do not…provide any evidence that wilderness water is an important cause of the disease in this country." The paper actually concludes on pp. 164-165 that the two outbreaks were probably *not* due to drinking backcountry water.

Ben

Hi Ben,

Thanks for your response. The two reported waterborne outbreaks among backpackers were "one each in Alaska and Washington." According to my reading, the cases he debunked were from Utah and Colorado. And it's clear that those cases weren't conclusively debunked, either.

I respectfully think you are making a big mistake in logic in your reliance on this phrase: The surveillance data of health departments indicate that giardiasis is a common communicable disease in the United States. They do not, however, provide any evidence that wilderness water is an important cause of the disease in this country.

I think it's likely equally accurate to say this "They do not, however, provide any evidence that poor wilderness hygiene is an important cause of the disease in this country."

As I related before, my last physician (Mammoth Lakes) said he commonly treats backpackers with Giardia. He doesn't report it to the health department. And he said something to the effect that as far as he knows none of his colleagues do either. I don't think health departments get very excited about individual hikers getting sick, so they don't track it. We've already agreed, I think, that lots of hikers get sick from Giardia. The health departments "do not, however, provide any evidence that wilderness giardia is an important cause of the disease in this country."(my words.) Doesn't mean it isn't to the many who get it.

"The surveillance data of health departments indicate that giardiasis is a common communicable disease in the United States. They do not, however, provide any evidence that wilderness water is an important cause of the disease in this country."

Since I haven't read the paper I'm going out on a limb here, but my interpretation of that quote is that only a small percentage of the giardiasis cases across the US can be attributed to wilderness water. Consider:

1. Most Americans eat food prepared by other people, have children in daycare, touch doorknobs, shake hands, or engage in similar high-risk frontcountry behavior.

2. Relatively few Americans enter the backcountry at all, and a smaller subset of those drink untreated water.

The proposition that giardia in backcountry water can be a significant risk to backpackers who drink untreated water, is not at all inconsistent with the quoted statement that it isn't an important cause of the disease nationwide.

We still get it high up in the Rockies in Canada where few humans actually tread. Unfortunately Marmots, bighorn sheep, and smaller critters exist at higher altitudes and Giardia presents itself as a significant risk. I have had two hiking buddies get sick with Giardia and they were using Pristine (AM in Canada).

For me – that's a fact.

Howdy Buck and Ben,

What buck said: "As I related before, my last physician (Mammoth Lakes) said he commonly treats backpackers with Giardia. He doesn't report it to the health department. And he said something to the effect that as far as he knows none of his colleagues do either."

Exactly what the doctor told me at Stateline Medical center in South Lake Tahoe.
He had treated many cases Giardiasis and said it was not an unusual event at the clinic.
One of my thru hiker friends in 2009 also tested positive for Giardiasis at Mammoth Lakes and was told the same thing by the doctor there. He had to wait 5 days for the test results!
Giardiasis is not life threatening. It really sucks and it's uncomfortable and in extreme cases like mine i could have collapsed.
But most cases are not as severe.
I don't think the CDC would have accurate information due to doctors not reporting all incidence.
The only real way to find out the truth about the safety of water in the back country is to test it again.
Every one of those studies quoted are over 10 years old.
I respect the effort in writing the article but I question age of the science and the small nature of the sample sizes.
I don't see how a valid conclusion can be made regarding the safety of backcountry water today based on the inconclusive evidence of yesterday.

The doctor I saw in South Lake Tahoe originally prescribed Nitazoxanide but the none of the pharmacies anywhere around the lake had it so i was re-prescribed Metronidazole which is the generic for Flagyl.
As an aside, I now carry a course of Metronidazole (Flagyl). Less than an ounce for 7 days worth of antibiotic. The caveat being not everyone tolerates metronidazole and nobody should take a course of antibiotic without reason. You can have a serious reaction to metro particularly if you happen to mix it with alcohol.
One of the interesting things about this antibiotic is that despite it's dangerous nature; liver toxiciy and side effects, it is readily availiable without perscription labelled as "Fish-Zole" at online veterinary supply sites.
I don't recommend anyone else use an antibiotic labelled for animal use even though I and apparently a lot of other Long Distance hikers have.
Better to get a perscription from a doctor before your trip. Good Luck getting a doctor to write a perscription before the fact though.

Repeating myself [a habit] backcountry water management is health risk management. For those who do not believe (and belief is part of this, as there's virtually no way to ascertain water quality, real-time in the field) their water supplies are contaminated by disease-causing microorganisms in meaningful concentrations–don't filter, don't treat, don't worry.

For those who suspect contamination, we have MANY treatment alternatives from simple to high tech. With research and field observation one can hopefully match the treatment to the situation, as these many alternatives do not address all forms of contamination equally well. Of course, technique and hygiene are necessary components of the scheme.

Has waterborne contamination been overhyped? Perhaps, but it's a big planet, water treatment technology has a worldwide market and water contamination is endemic in significant parts of it. Closer to home, can somebody backpack parts of the Sierra Nevada and not encounter waterborne contamination on their trip? Yes. (But, which parts at what time of year?) Can somebody thruhike the California PCT, or even the JMT, and not encounter waterborne contamination? No.

See the difference?

These discussions often get hung up on Giardia, which frankly becomes a distraction from the larger issue of water quality. When, say, drawing water from a lazy stream running though a cowflop meadow in September–because it's the only available water for miles–do you really care whether Giardia itself is present when bacteria and viruses are, with certainty?

Luckily the decision remains a personal one (not mandatory like bear canisters) but I consider it unethical to advise anybody that water treatment is unnecessary because there is no contamination.

Prost,

Rick

Echoing Rick's post somewhat…

Given the wide array of treatment from nothing to the elaborate, given how we are all different as individuals, and finally how we are dealing with the unseen out there — all this is a bit like religion. It's good to lay out the options — but fruitless (if not nonsensical) to argue whether treatment is necessary or which method is best for everyone…

Benjamin, part of the problem is that too many backpackers do not know how to think about water quality. Unfortunately, we do not carry subminiature water quality labs around with us (although that would be a neat product).

I think about the elevation of the water first. In California, for example, there tends to be snow up high that melts through the spring and summer. If you can get very close to that newly melted snow water, it is almost foolproof. Yes, I have seen muddy little paw prints in the snow. If I can drink the meltwater as it first drips off the snow field, I generally don't treat it. As soon as the water has been running along the ground for a way, I generally treat it with something. Maybe it is a quick trip through a gravity filter. Once the water has been sitting around in a lake, I tend to get a bit more thorough. Maybe gravity filter plus some bleach drops. On extremely rare occasions, I have used iodine and have boiled the water also.

I don't believe that I currently operate in any areas downstream from grazing animal herds.

–B.G.–

Something is making a lot of people very sick. Convincing people to change their minds one way or another might be like shooting for a religious conversion, but this is real world stuff. Some things are provable, some unprovable. It's important that people make their own rational decisions and they need to hear both sides.

Of PCT thru-hikers last year, J. L. and M. L. also got Giardia. they were religious about filtering water after getting sick from giardia in the High Sierras C. D. got Giardia somewhere in that general area, I'm not sure where. P. was hit by Giardia, in the Sierras, and it took her off the trail. L. got Giardia south of Mojave. B. M. came down with it in Oregon. R. said he had it, I don't know where. R2. also. Don't know if either of the latter were tested or where they got it. And of course, me. That's just those I know about. (names abbreviated in the interest of privacy.)

It was J. L. that told me about Tinidazole to treat Giardia. It is new on the U.S. market, and has proven to work the best for most people.

"…backcountry water management is health risk management."

Right, risk is frequently defined as 'probability of occurrence x severity of consequences.'

So you can choose the level of risk to tolerate, eg, if you are on a frequently traveled trail that isn't more than a day from definitive medical care, or if your trip is only a few days, and you (and your group) are not that bothered by bailing on the trip when someone gets ill, then maybe you're comfortable with less rigorous water treatment.

OTOH, if you are going somewhere really remote for long periods, are in a foreign country without good medical care, are not carrying a satphone or extra food, water treatment chemicals, underpants etc. then maybe more water treatment is in order because the consequences of getting ill would be worse.

Getting at 'probability of occurrence' is harder…

"Good Luck getting a doctor to write a perscription before the fact though."

I have never had any difficulty getting my docs, there have been several, to write me an Rx for Cipro or Bactrim when I explained their intended use(hopefully none) and my protocols for deciding when to employ them. It's a matter of trust. Ditto for Hydrocodone, especially Hydrocodone.

Yes, before I travel to some third-world country on a high climbing expedition, I always request of my physician three items: Bactrim or some broad-spectrum antibiotic, Diamox for altitude, and some prescription-strength pain killer. Typically, he makes me describe how or why I would use each of those. Then, when it all makes sense to him, I get the prescriptions. I suspect that I could request Flagyl also.

Lots of big hospitals and HMO centers have a travel clinic. Often, they are even more experienced with strange drugs for strange places. They do injections, malaria drugs, and everything else, but you have to show them that you know where you are going and how long you will be there.

–B.G.–

"Unfortunately Marmots, bighorn sheep, and smaller critters exist at higher altitudes and Giardia presents itself as a significant risk."

+1 I drink water untreated about half the time in the southern Sierra, almost exclusively off trail, but I check VERY thoroughly for scat in the general area before making the decision whether or not to treat. Still, it is a calculated risk, modulated by instincts born of long experience in the area. Everyone has their decision making process, which is as it should be given that the consequences are very personal. I hypothesize that an additional benefit is that this reinforces the connection between actions and consequences in general, a connection ever more rarely made by the population at large, IMO. Maybe if everyone was responsible for their own water quality, insurance would be cheaper and we'd have a lot fewer people in jail? Sorry if I digress, but the connection was just too obvious, at least to me. ;-)