My goal is to get rid of my 1 lb. MSR filter this year, but can not decide what route I want to go.

1.) What contaminates do I need to treat? For camping in the northern (US) rockies, and filtering water from small streams, I was always under the impression that Viruses were low risk, and so only used a filter. Is this common practice?

2.) How common are cysts? (US rockies). I could switch to purification drops and save a bunch of weight, but I understand it would take up to 4 hrs. to kill cysts in cold water.

3.) If cysts are a threat, any input on a simple/lightweight prefilter to along with purification?

No viruses in U.S.

Bacteria seldom a problem.

If you're in the mountains, you probably don't even need to worry about Giardia

I use nothing half the time and Adventurer Opti half the time

Chlorine tablets or drops are most common for lightweight backpackers but I don't like the taste or injesting chemicals that are probably worse than the Giardia risk

Good article

> No viruses in U.S.
Hysterical mirth, followed by an appalled terrified shudder. This is absolutely WRONG!

ANYWHERE there is a risk of faecal contamination there are viruses and bacteria, and potentially protozoa as well. And that is 'faecal', not just 'human faecal'.

Now this does not mean you have to be paranoid about treating every drop of water, but it does mean you need to be careful where you get your drinking water. Known danger spots are downstream of any human habitation - and that includes towns with sewerage treatment plants as well as single houses, around popular camping sites, and downstream of farms. I won't go into details about these.

We carry an Adventurer Opti on most trips, but very often do not use it. Small creeks with known clean catchments are usually just fine in our experience. But we check.

Cheers

Okay Roger, maybe not never, but that's what people say : )

Fecal contamination is usually Giardia or bacteria, like E Coli

Another thing I have heard but not confirmed is that water near surface of lake is okay because UV light from sun kills bugs

I have read bacteria range from .2 to 10 microns. I could capture some of them with a 1 micron prefilter...

Is there any correlation between the size of the bacteria, and our ability to naturally resist it? IE: is a 5 micron bacteria more resilient to our bodies than a .5 micron bacteria?

The water risks that you encounter depend a lot on where you pick it up. For example, if you are downstream from a village in a third-world country that has no facilities, you stand a chance of picking up a viral or bacterial problem. [I saw a lot of that in Nepal.] You can knock out a lot of viral or bacterial risk with boiling or chlorine/iodine treatment. Still, you want to look around to avoid some decomposing animal carcass in the water just upstream from you.

If you are picking up raw water from a still lake at 7,000-9,000' elevation in California, you stand a little chance of viral or bacterial problems, but Giardia is more likely, but still nowhere near a certainty. The risk increases if you are downstream from cattle or other domestic animals. Note that Giardia exists in two forms. One is the cyst, and it is tiny, maybe only 2-3 microns, and it is a hard little egg. Filters, chlorine/iodine, boiling, or maybe UV will work. The other form is the adult, and it is much larger, maybe 25-35 microns, so the simplest filter will knock it out.

If you are picking up cold snowmelt at 13,000' elevation in California, you stand little chance of any risk, but that does not mean absolutely zero risk. If there is a big snowfield with no muddy little mammal tracks, then you are getting much closer to zero risk. I've seen lots of muddy little mammal tracks above 13,000' in a few places like Mount Whitney.

Chemical risks are easier to predict. In the U.S., most serious chemical risks will tie to mining residue or to the actual ores being mined. Many mines are marked on maps and controlled by the feds, so they are not hard to avoid. I would not drink the water flowing out of a mine or especially from the area of a ore mill, but a mile upstream from it the water is probably great. I don't operate around many mines, so I don't worry about this. You want to understand the term "heavy metal."

Due to where I operate in California, I use a 2 micron gravity filter routinely. Then I also have some chlorine bleach that I add if I am paranoid that day. Although it is possible that I got some strange water, I have not had any such symptoms in forty years now, since I was in the Army and got water in the field.

--B.G.--

I was thinking about using a similar practice. Making a homemade prefilter using something like this

http://www.cfsco.net/fibagsvowvob3.html

(I got the idea from this video)

http://www.youtube.com/watch?v=is7X6JS9vUo

and then using aquamira when the source looked questionable. Anything that gets past the 1 micron filter should be quickly and easily killed by the aquamira... Right?

>> If you are picking up cold snowmelt at 13,000' elevation in California, you stand little chance of any risk, but that does not mean absolutely zero risk. If there is a big snowfield with no muddy little mammal tracks, then you are getting much closer to zero risk. I've seen lots of muddy little mammal tracks above 13,000' in a few places like Mount Whitney.

I agree. Snow melt runoff poses negligible risk, but it's not risk-free. Hiking the Rae Lakes Loop (central California, 6,000 to 12,000 feet), we'd sometimes run across patches of pink snow with no signs of disturbance (mammal tracks or otherwise). I read somewhere it was an algea, and that it could make you sick. Thankfully, even I'm not dumb enough to try it, so I don't know from personal experience.

So I guess the adage should be... "don't eat COLORED snow", and don't assume that snow melt is always clean.

To the original poster: Setting up a 0.2 micron gravity filter will cost you $50 and less than 4 ounces. Maybe not SUL, but light enough for most.

My setup weighs less than my 1 lb. MSR, but what I like best about it is it does all the work. My steripen is a little lighter, but you have to sit and stir. I find it tedious to do that for two or three liters of water.



The main filter is a 0.1 micron Sawyer gravity filter. It gets all celled pathogens. I add the CDC recommended amount of chlorine bleach to kill viruses. The gray filter is a Katadyn charcoal filter which removes the chlorine after it's done its work. It gets other organic contaminants too. Not shown is Platy dirty water bag that screws onto one end of hose. Other end snaps into hydration bladder. The water I get tastes better than anything that comes out of a bottle.

But as I said, the best part is, you hang the filter apparatus from a branch and while you eat an apple or a piece of cheese, or hang your hammock, or read a couple of pages, or start a fire, your water is being purified with no more help from you. Filter can be back flushed in the field and is warranted for life.

Edited by herman666 on 01/28/2011 19:16:00 MST.

Some more info on a .2 micron gravity filter would be great. But I have a couple concerns with something like that.

1.) I dont like to carry a whole bunch of water while I hike, and have gotten used to the idea that I can stop and quickly pick up more water anytime I see it. Unless I can use the gravity filter on the go, I dont know if i would like the idea of having to wait for camp to refill water.

2.) I also have concerns of a .2 micron gravity filter clogging easily? Usually where I hike water is clean and abundant, but there are always times when thats not the case. I like having the peace of mind of a fail safe system.

"pink snow"

We call this watermelon snow. It is a pale red color, and it typically shows up in the late spring and early summer. It has a faint watermelon smell, hence the name.

When the sun is baking on the snow surface, a thin layer of water forms. Pine pollen in the air settles there, and an algae grows on that which is red. If it is concentrated in the melt water, it won't make you tremendously sick, but it may cause a one-time bowel disturbance. Think of it as an instant weight-loss plan.

It is plant-based, and it does not propagate inside you, so there is no long-term problem. It is very easy to avoid. If you must eat snow, then scrape the top surface off and discard it. Then grab up a handful of snow from 1-2 inches down. It is only the top surface that supports watermelon snow.

--B.G.--

I got this Sawyer water filter kit from Wally World: Sawyer Water Filter. It includes the same Sawyer filter as in the post above, a couple extra short lengths of hose, and a couple zip-ties to convert it to a gravity filter (you supply the water bladders). On my analog postal scale, it weighs about 1.75 ounces dry (the bottle weighs another 7 ounces, but I gave that to the kids). Re-reading the box, it appears it's actually a 0.1 micron filter.

$34 for the filter, $15 for a Platy, and you've got a gravity filter.

How does this work as in inline filter? ie: Just sucking water through a hose with the filter inline to the dirty platy?

> Is there any correlation between the size of the bacteria, and our ability to naturally resist it?
None whatsoever afaik.

Cheers

No, bacterial size does NOT matter for infectivity. Though it is true that the largest cells (a common egg cell) is eaten as food. Normally you body just digests any bacteria pretty much the same way. The really tiny viruses are typically debated as being truly "living". They are mostly just bundles of DNA and attack bacteria. Again, your body will simply digest them.

Unless you have highly expensive filters, most are simply statistically designed. They lay out layers pretty much randomly. Soo, typically, they design a .1 micron filter, and sell it as a .2 micron filter, knowing it will catch most things at .2.
A scientific filter may cost hundreds of dollars. These are absolute and will NOT pass anyhing other than 1 micron. That said, I would not worry to much. Your body has been dealing with that stuff throughout evolution. Most stuff might make you "scoot". If you are immune compromised, boil the water.

Viruses and bacteria in the water can be bad. And yes. In the US as well as the rest of the planet, you may find some, as Roger says. The big difference in the US is that if you were born in the USA, then you probably were immunized against the worst of these. Polio, smallpox, hepatitus, and a host of others. You are likly immune to them and can ignore these. NOT from fecal mater, bead and decaying tissue, etc, though. Use normal caution, use ALL your senses: taste, looks, smell and feel.

I have drunk from lakes in the ADK's for many years. Then I heard that the upper layers were pretty clean due to UV. Soo, I cannot say whether this is true or not, since the lack of evidence says nothing. But, I would not recommend trying this near shore. The wave action churns up too much crap in the water. In a canoe, I would not object, though.

I treat mainly for bacteria and viruses. Crypto, Gardia, I pretty much ignore. If I have a case of the "scoots", it will likely NOT be out camping. It takes a week to a month to develope.

Tapeworms are another concern. UV is not that effective on macrobiotics. Filtering is good. Boiling always works.

Regular hiking filters don't filter out viruses, the viruses are too small.

These filters are recommended and widely used.

There are few cases reported of such people getting sick.

Conclusion - viruses aren't a problem in the U.S.

On the other hand, people get sick routinely and it's possible some of that is from viruses in drinking water. The whole issue of treating drinking water is very confusing. You probably don't need to treat water at all, at least in most cases.

"Then I heard that the upper layers were pretty clean due to UV. Soo, I cannot say whether this is true or not, since the lack of evidence says nothing."

A lot of lakes in the Adirdonacks are in fact sterile (and hence lifeless, leading to their crystalline clarity)... due to acid rain.

"A lot of lakes in the Adirdonacks are in fact sterile (and hence lifeless, leading to their crystalline clarity)... due to acid rain."

Untrue. The acid rain was only bad in the ADK's because it was also destroying the fishery. No fish means fewer tourists. When your entire livleyhood depends on the tourist trade, it becomes a major big deal.

The Brook Trout live in highly acidic water to begin with. Soo, the small push from acid rain did a lot of damage to that species. Mostly the decline in the fish was because of the introduction of forign species, though. Not due to acid rain, though some was.

I lived up there for several years and could see the effects of a lot of that. Now I spend only 30 nights per year up there, but still have a lot of friends up there.

Many of the insects were killed off as the acid levels changed. Many of the lakes are also "panned". Depressions in the bedrock. The granite and limestone tends to mitigate the effects of a lot of the acid rain. Even those lakes that were "killed", still contained a large aquatic environment. Deer, bear and other animals would drink the water, too. Mayflies were killed off, but some insects thrived. Biodegradation still happened, decay of organic materials did not halt. Acid rain only shifted the balance, it did not kill all life. Acid rain has largly been reduced. As of about 5 years ago, there was some encouraging signs. Trees were comming back on the western slopes and the ones that were there appeared to be healthier. Anyway, it is incorrect to think of acid rain as a killer of everything. There has to be a really low PH for this to happen. Mostly, a disruption of what was and a new balance will be reached. I am please with the progress of the lakes and waters...especially those hardest hit. Just do not spread it around...we still need the support that only a federal government can provide. But, that support means the ADK's will be viable beyond my lifetime. And it also means it will take time to recover (whatever that means) from the acid rain.

"Untrue. The acid rain was only bad in the ADK's because it was also destroying the fishery. No fish means fewer tourists. When your entire livleyhood depends on the tourist trade, it becomes a major big deal. "

It was a big deal when I was growing up there -- several rangers showed me lakes that were clear largely because of the deleterious effects of acid rain.

However, that was a long time ago -- nearly 20 years -- so a lot could have changed in that time, and it sounds like the changes have been an improvement!

Growing up I drank water in the Sierras without treating it and didn't even think much about it. Now I work in the public water industry and am quite aware of the potential health problems. I'm very suspicious about the effectiveness of the portable UV devices: i haven't tested one in the lab or anything, but theoretically I just can't imagine having a long enough contact time with the organisms to render them sterile with the way these devices work compared to the way industrial UV water treatment works.

I still feel boiling is the fail safe method to render you safe from bacteria, viruses, protozoa, and parasites. You'll read all sorts of conflicting info, but basically, as soon as you see the water get to a real boil, just take it off. It'll spend enough time at hot enough temperature on the way up and way down from the boil to knock everything out for you (basically 180 degrees for one minute will do it). Coffee filter it first if the source has a lot of suspended solids, and aerate afterwards to improve the taste.

Too bad it's time consuming and fuel intensive.