Drinking Stream Water

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ghosting
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Drinking Stream Water

Post by ghosting » July 26th, 2017, 11:17 am

So....

I did some miles on the PCT over the last two days (Stagman Ridge - Horseshoe Meadows - Riley Camp on Mt. Adams) and, due having a new filter and not paying attention...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?

Thanks,

- Jason

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adamschneider
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Re: Drinking Stream Water

Post by adamschneider » July 26th, 2017, 11:36 am

It all depends on whether or not anyone or anything recently pooped upstream. You'll PROBABLY be fine.

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retired jerry
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Re: Drinking Stream Water

Post by retired jerry » July 26th, 2017, 12:23 pm

This can be controversial. Flame wars can ensue :)

I treat my water about half the time, maybe more just because it's so easy and I always carry my filter.

I've never got sick that I know of.

Reading about this, it's statistical. If you drink water all the time you'll likely eventually get sick. One time probably not. Some people get infected without symptoms. Some people are sensitive and get sick easily.

Any responsible person would recommend treating water, but if for some reason you can't like your filter breaks, then drink anyway. The risk of dehydration is bigger than the risk of illness.

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drm
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Re: Drinking Stream Water

Post by drm » July 26th, 2017, 1:26 pm

The Riley Ck trail hits Riley Meadows and Riley Creek after the northern dogleg at about 5500 feet, so there really is no access to Riley Ck below that. I was just there last week and the creek was running kind of low for the time of year. Like Jerry I don't always filter, but as low as that creek was running, I would probably have done so.

Clear is nearly meaningless. Fast moving water doesn't kill bugs but it does deter them from multiplying, so that helps. But if it was stagnant somewhere above that you don't know about, fast moving where you are doesn't help much. I'd say your odds of getting anything are quite small, but a lot depends on how sensitive your digestive system is. If you have a sensitive digestive system and often get symptoms from odd foods, you have a good chance of getting some discomfort. But I think the odds of getting giardia are pretty low. Note that for most people, it takes about two weeks get get symptoms for giardia, assuming you get symptoms. It's possible to get it and never feel anything.

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adamschneider
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Re: Drinking Stream Water

Post by adamschneider » July 26th, 2017, 2:25 pm

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.

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drm
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Re: Drinking Stream Water

Post by drm » July 26th, 2017, 3:49 pm

Yeah, I wonder how many people assiduously filter water from a lake, and then go for a swim in it.

Webfoot
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Re: Drinking Stream Water

Post by Webfoot » July 26th, 2017, 7:13 pm

I don't think swimming is nearly the exposure that drinking is. At least I hope not as I'll swim in the Columbia but I'd never drink out of it. Am I misinformed?

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Don Nelsen
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Re: Drinking Stream Water

Post by Don Nelsen » July 26th, 2017, 7:53 pm

Webfoot wrote:I don't think swimming is nearly the exposure that drinking is. At least I hope not as I'll swim in the Columbia but I'd never drink out of it. Am I misinformed?
I used to do a lot of waterskiing in both the Willamette and the Columbia. It was inevitable that I would swallow some water when I crashed as I usually did at least once. I always had some intestinal problems as a result! It was just part of the deal but not so pleasant the next day or two. I also used to do the occasional swim across the Columbia river and mid channel, the waves would sometimes give me a mouthful of water. Same result as when waterskiing. It's really difficult to not swallow a least a little water when swimming.

BTW, I've very rarely filtered water and drank out of many streams in the NW and never had a problem. Our two big rivers, not so much.

dn
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Aimless
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Re: Drinking Stream Water

Post by Aimless » July 26th, 2017, 8:58 pm

is it just gonna be luck of the draw?

Yup. It is my understanding that the critical variable is the bacterial or parasitic load that happens to be in the sample of water you ingest. This is entirely hit-or-miss. You could dip a few ounces of water out of Riley Creek 1000 times and your exact odds of getting a significant load of bacteria, giardia or cryptosporidium would depend entirely on how many of those samples had a reasonably high count. Most would be totally zero. Your ingested sample could be the unlucky one.

But, if I were to advise you on your odds, I'd say don't give it another thought unless you begin to show symptoms. You almost certainly won't. Contamination at that elevation is going to be very rare.

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buckwheat
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Re: Drinking Stream Water

Post by buckwheat » July 27th, 2017, 5:38 am

I try to filter when possible, but as stated it isn't always possible. When I was younger I rarely filtered and never got sick as a result of it, but I'd imagine on longer outings its more critical to keep yourself healthy. If youre just gone for a weekend and start getting the runs on the end of Sunday, youll be back in civilization in an hour or two, and minimize any serious risk, but if you're going to be gone for a week, and you get sick on day 3, and you're 60 miles from your car, that is a much more serious issue. Gotta weigh the pros and cons.

One thing I heard that was interesting that I'd never thought about, and I don't know how accurate it is, but that still clear water is safer to drink than moving clear water because if its still, and in the sunshine, the UV light from the sun will effectively UV filter the top of it, and turbulent water doesn't get this natural UV sanitizing effect. I haven't looked into the actual research behind this though, so who knows if its just something told to calm down a panicked hiker during a time of thirst.

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