Drinking out of lakes vs snow melt/running water

[Rafi Harzahav]

Hi,

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?

Thanks,

rhz

[Keith Bassett]

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.

K

[Nathan Hays]

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]

think of filtering as " insurance"

If you filter . .you're covered

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

[Rafi Harzahav]

Hi,

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.

thanks,

rhz

[M B]

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

[Erik Basil]

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]

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]

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]

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]

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.

–B.G.–

[Harrison Carpenter]

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]

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.

–B.G.–

[Robert Cowman]

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.

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