Drinking Stream Water

[sparklehorse]

This is old news, but someone did an interesting meta-analysis that concluded:

Published reports of confirmed giardiasis among outdoor recreationalists clearly demonstrate a high incidence among this population. However, the evidence for an association between drinking backcountry water and acquiring giardiasis is minimal. Education efforts aimed at outdoor recreationalists should place more emphasis on handwashing than on water purification. Further studies should attempt to separate the specific risk factor of drinking water from backcountry sources from other behaviors among this group that may contribute to the risk.

This is why backpackers should universally adopt the fist bump in place of the hand shake. Many thru hikers do this already. Also not share food like trail mix, unless you know with great certainty that your friend has impeccable bathroom hygiene standards.

correct me if I'm wrong but I thought the only wild water consumption threats are parasites or viruses and we don't have viruses here and the only threat we have in our PNW region is giardia?

Bacteria can also be a concern, like from the rotting elk carcass you can't see that's lying in the stream a half mile away.

Personally I think the risks of drinking wild water are low if one chooses their water sources carefully, but as has been mentioned, filtering is wise unless you can acquire your water at or very near the source.

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[drm]

I understand the attraction of this idea, but it doesn't take much imagination to come up with a thousand situations where what doesn't kill you leaves you permanently damaged and chronically weakened. In other words, it's a bogus piece of pseudo-wisdom.

It's not pseudo wisdom in my opinion, but it is playing the odds, which we all do all the time. There is no question that the immune system learns from challenges and in many (though not necessarily all) cases responds more quickly and strongly to threats it has dealt with before. If you want to be 100% safe with your water, what other risks do you take in your regular life? I do not think that getting sick from water is likely to leave you "permanently damaged and chronically weakened", but there are many things i normal life in the city that could.

I have a list of conditions that I use to determine whether I filter my water. They include the source of the water, if known (and visible), the volume of water (for dilution), movement of water (never from lakes) and the temperature of the water.

[BigBear]

I do recall the photos in the Lowe's hiking guides (circa 1968-73) that often featured a metal Sierra cup being dipped into the refreshing mountain stream. I have on occasion, although not in the past decade, drank untreated mountain-fresh water. However, I cannot recommend the practice of drinking untreated water in the backcountry.

If you are substantially dehydrated and the water is likely undamaged by cattle or humans, drinking the water is less problematic than continuing to dehydrate.

The other consideration in drinking mountain stream water is glacial silt. The quartz crystals are like drinking glass shards to your intestinal system. So, make sure its clear and not "floured."

Drinking from a lake or pond, never did it, not even in the 80s when water was more likely to be safe. Whereas mountain streams were only flowing above-ground for a few minutes or hours, lakes have been there to accumulate impurities for months, or even years. Much less safe.

[kepPNW]

Basically, giardia is the hiking boogeyman.

It's not pseudo wisdom in my opinion, but it is playing the odds, which we all do all the time.

Bingo! (x2)

[pcg]

The other consideration in drinking mountain stream water is glacial silt. The quartz crystals are like drinking glass shards to your intestinal system.

Either this is an old wive's tale or I have iron intestines.

[Koda]

correct me if I'm wrong but I thought the only wild water consumption threats are parasites or viruses and we don't have viruses here and the only threat we have in our PNW region is giardia?

I agree the risk is low but the consequences are high. I have a friend that got giardia once here and said it was hell to go thru. An onset of giardia outdoors especially on multi day backpacks far from the trailhead can be quite dangerous...

Yes, viruses are not an issue in the wild in N. America; our water issues are bacteria and protozoa. The period of incubation for giardiasis is 1-2 weeks, so you're unlikely to start getting symptoms while you're still outdoors. This is part of what makes it so hard to definitively connect the illness with the source of the infection. And as others have noted, the most common culprit is improper sanitation (hand cleaning) rather than water sources. Besides which, most intestinal problems are probably not caused by giardia, but rather by other bacteria (e. coli, for instance, if you don't wash your hands well).

I drink untreated water periodically in small/medium amounts (with no ill effects) but know many people who refuse to do so. Almost all of those people will cite some apocryphal person they know who "got giardia." Basically, giardia is the hiking boogeyman.

From a well-known and oft-quoted report on giardia levels in Sierra Nevada water sources (which found that common levels in the Sierra Nevada were well below what is legally allowed in the SF municipal water supply):

Sierra Nevada water has far too few Giardia cysts for you to contract an infestation from it. Even if you go somewhere where the concentration is high, you probably won’t get giardiasis. If you do get giardiasis, you probably won’t have any symptoms. If you have symptoms, they will probably go away by them­selves in a week or so. If they don’t or you develop serious persistent symptoms, you should seek medical treatment. Finally, those contracting giardiasis may develop immunity to it, thus lowering the likelihood that they will get it again.

There is certainly no reason for anxiety about giardiasis. Fewer than 1 percent of those who have an infestation, or about 5 percent of those with symptoms, need medical help.

good info to know and glad to hear the incubation period is long enough until after most all trips outdoors.

Its interesting all the technology and sales in backpacking water filters because of the giardia boogyman.... yet I'll still lug mine around but it makes me wonder if all we need is a simple kitchen sieve to filter out the big stuff? ...or is bacteria and protozoa still a concern? (or perhaps the real concern)

[retired jerry]

giardia (and crypto and bacteria and ...) aren't really boogeymen, although maybe the risk is exaggerated

there are cases where people test positive after drinking untreated water

I'm too lazy to link to good studies

I don't think the big things you can remove with a sieve are a problem. You need a filter like Sawyer Squeeze or Steripen to get the bugs that are a problem

[buck3m]

...I may have drank 3 - 5 oz of unfiltered stream water from Riley Creek (about 5000 ft elevation?) What are my chances of getting "the fever"??

Anyone has opinions on drinking from clear / fast moving streams? I know you can never be sure...is it just gonna be luck of the draw?...

Odds are you'll be fine. Personally, I wouldn't drink untreated water again but I also wouldn't worry about drinking some untreated water by mistake unless I got symptoms.

Clear, fast moving streams as well as springs have often tested positive for giardia and other pathogens. Again, in most cases you'll be fine but there is risk no matter how carefully chosen any surface water is. As the EPA says: [giardia] Cysts have been found all months of the year in surface waters from the Arctic to the tropics in even the most pristine of surface waters...

The Rockwell and Welch papers are quoted here as they usually are in these discussions. Neither of them were writing in their area of expertise and both the quoted articles/papers are over 20 years old, and do not reflect our current state of knowledge.

For example, there are verified outbreaks of waterborne giardiasis among backcountry campers and backpackers and, as far as I know, not a single verified case attributed to poor hygiene.

I read the Rockwell article before hiking the PCT. He says "Sierra Nevada water has far too few Giardia cysts for you to contract an infestation from it." That is absolutely false. I believed him, drank untreated water in the Sierra and got giardia. I looked into his writing and found out he was wrong on virtually all of his major points. http://bucktrack.com/Giardia_Hiking_Water.html

Welch makes his case by dismissing most of the available research and then concluding the hygiene is a greater factor without citing data to prove his point. That's science?

Nobody knows the exact risk from any given untested water source, (there's no doubt that MOST people will USUALLY get by without treating) but here's what the professional epidemiologists at the CDC say Although the advice to universally filter and disinfect backcountry drinking water to prevent disease has been debated, the health consequences of ignoring that standard water treatment advice have been documented…

I've put together what I believe to be the most comprehensive list of scientific papers on the subject here: http://bucktrack.com/water.html

I wrote a more readable article about the topic in a guest post here: https://thetrek.co/should-you-treat-wat ... ence-says/

[Koda]

I don't think the big things you can remove with a sieve are a problem. You need a filter like Sawyer Squeeze or Steripen to get the bugs that are a problem

my thoughts were that since the risk is low just sieve out the big stuff and drink.

[retired jerry]

don't worry about the bigger things? I can usually get water with few.