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Drinking out of lakes vs snow melt/running water
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Rafi Harzahav
(rhz10) - F

Locale: SF Bay Area
Drinking out of lakes vs snow melt/running water on 06/13/2012 13:03:29 MDT Print View


Last time we were in Emigrant Wilderness, we found ourselves filtering and drinking more out of lakes than snow melt or other sources of running water. Sometimes I felt a little strange about drinking from a water source that served as a swimming hole for eager-to-be-refreshed backpackers (who were no doubt covered in sun screen and deet) or as a drinking hole for horses who took dumps at the edge of the lake.

Is there something to be concerned about here, or am I just being paranoid?



Keith Bassett

Locale: Pacific NW
Filtering on 06/13/2012 13:33:17 MDT Print View

Filtering is the key phrase in your post. :)

As long as you filter, you are probably going to be just fine.

We drink untreated snow melt from fast flowing streams in the PNW all the time, and I have only been sick once when I was a teen. I suspect that was a hygiene issue, as I look back at it now.

We just try to be certain that the stream isn't one that crosses the trail further up, in which case it gets treated.


Nathan Hays

Locale: San Francisco
Filter on 06/13/2012 16:30:25 MDT Print View

Be sure where that runoff is coming from if you don't filter. I recall pumping away at a stream when a tromp of packers all dunked their nalgenes to fill up right where I was pumping from. Not even 400 feet up, the trail crossed the stream a second time but this time it was flowing through fresh horse manure.

Scott Smith
(mrmuddy) - MLife

Locale: No Cal
Drinking out of lakes vs snow melt/running water on 06/13/2012 18:57:52 MDT Print View

think of filtering as " insurance"

If you filter . .you're covered

If you don't you betting on .. " I'm safe"

Rafi Harzahav
(rhz10) - F

Locale: SF Bay Area
deet/sun screen in water... on 06/14/2012 09:32:19 MDT Print View


Thanks for the responses. I'm also wondering whether it's possible that the concentrations of deet and/or sunscreen would present a health risk. Presumably the filter would not address chemical contamination of this type.



deet and sunscreen on 06/14/2012 22:44:13 MDT Print View

likely less in the extremely dilute amounts (likely totally non-detectable) than the health risk from rubbing it on your skin.

Erik Basil

Locale: Atzlan
Stream of thought on 06/28/2012 07:35:57 MDT Print View

I prefer running water where available, because it's oxygenated by the tumble over rocks and such. I still filter for bugs and to cull out the flecks of dead moose flesh, etc...

Matthew mcgurk
(phatpacker) - F

Locale: Central coast California
filtering on 08/18/2012 14:51:19 MDT Print View

Youve carried the filter why not use it. Ghiardia in the backcountry would be misserable. Every lake gets filled somehow. I look for the source because it tastes better, If it is just snow melt and the source is gone just filter and drink. Water is something that I enjoy when I am out in the backcountry so I look for the best sources and load up

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: filtering on 08/18/2012 15:27:12 MDT Print View

I've read that the red stuff (Chlamydomonas nivalis, "watermelon snow") growing in old snow is not good--- and never wanted to be the test dummy to verify that. It came to mind when talking of snowmelt into a small tarn.

Filter if you have a filter, or boil, or treat with chemicals. Being a Technicolor fountain far from home is never good.

Harrison Carpenter
(carpenh) - M

Locale: St. Vrain River Valley
So which is which? on 08/19/2012 15:44:32 MDT Print View

Pardon what must sound like a fantastically stupid question, but I have to ask: so, is it more important/advisable to filter, or to treat, or must one do both?

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: So which is which? on 08/19/2012 17:00:11 MDT Print View

Harrison, there are different risks in the water in different places, so you want to treat your water properly depending on the risks for your area. In some places, the risks are best removed by filtering. In other places, the risks are best removed by chemical treatment. In still other places, UV light might work good, and boiling nearly always works. There are a few places where I do not treat water at all, but these are generally right where the snow patch is melting.


Harrison Carpenter
(carpenh) - M

Locale: St. Vrain River Valley
Re: on 08/19/2012 18:10:24 MDT Print View

Thanks, Bob. I've always operated under much the same principles, but the more I read about backcountry water the more confused I get.

In my pre-UL days, I carried a PUR filter/purifier. I've been trying to learn how to effectively use chemical treatments and UV light; both, of course, have no "filter" in the system. That's made me wonder just how necessary it is to pre-filter water before treating it with, say, AquaMira or a Steripen. Believe it or not, it's been difficult to find clear statements about it.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: water on 08/19/2012 18:31:22 MDT Print View

Nearly all treatment systems will get some benefit from pre-filtering the water before your main treatment. But that may or may not be necessary.

Most UV light treatment works poorly in dirty/turbid water, so that is one case where pre-filtering should help. In fact, if possible, let the raw water stand in a container. After just a few minutes, glacial silt and similar crud will settle out to the bottom. Then just treat the top 90% of the raw water that is clear, and you've already made some progress.


Robert Cowman
(rcowman) - F

Locale: Canadian Rockies
Re: Re: Re: water on 08/19/2012 19:17:52 MDT Print View

I stopped carrying treatment a few years ago. just pull all my water from moving water up here and i havent gotten sick. seen plenty of people carrying filters and somehow getting sick probably because the dont wash there hands or improperly prepare food.