Water Filter Question

I just bought a water filter, a MSR Miniworks EX, so I don't have to carry as much water. I've been reading up on filters for a while but I have one question that none of the forums or even the instruction manual seem to answer clearly. If the water filter will not filter out viruses, where can I safely use the filter? It seems that anywhere I would be using the filter there is some contamination - agriculture runnoff or towns along a river that I'm sure dump all sorts of things in the water.

Maybe I'm missing the point of a water filter. I don't want to get sick, but would rather travel light so I can enjoy my trip more. I'm thinking about taking the filter back and just carrying water with me.

Most water filters will not remove viruses or chemical contamination (agricultural runoff of pesticides and fertilizers, for example, or industrial wastes, such as the mercury salts found here in the SFBay area in Almaden Valley and the parks in that area).

But in most areas these are very low risk. Certainly in areas such as along the Appalachian Trail, in the White Mountains of NH, Adirondacks, Rockies, Sierra, European Alps, etc, the risk is very low. The places where the risk of viruses is significant are those in which sanitation is poor (many 3rd world countries). Chemical contamination is generally pretty well known, though even along the Ohio, Mississippi, and Missouri systems, the volume of water is great enough that the contamination is low enough to not be a problem for the occasional user out for a few weekends a year. Actually, the risk for the resident of, say, Baton Rouge, who drinks treated water from the city water supply is higher (the statistics on cancer for Baton Rouge residents are higher than, say, St Louis for those cancers that appear to be related to the carcinogens found in the city water supplies).

That said, there are water filters that have carbon elements that at least partially remove the chemical contaminants, and there are methods of killing the viruses (iodine and chlorine compounds and resins in certain filters).

Your main risk from the water is actually bacteria and larger organisms like giardia. The Miniworks and other backpacking filters do just fine with those.

There are some other approaches as well, which I spent time looking into before my December trip to Africa. I am supposed to write an overview and my own experiences up for Trailspace, if I can just get a few more things out of the way. But just briefly -

Filters - all do just fine on bacteria and protozoa. Some do ok on viruses of concern. Some will reduce chemical contamination (not eliminate, though)

Boiling - heating the water to 155F or greater will kill most organisms, including viruses. Some protozoan cysts will survive, but are killed if the water is held above 155F for a few minutes. Actual boiling is not necessary until you get to extreme altitudes (like on Everest).

Chemical - iodine and chlorine dioxide (and sodium hypochlorite = bleach) will kill bacteria, protozoa, and viruses, given sufficient time. But it is 30 min for iodine (and some people are sensitive to iodine), 4 hours for chlorine dioxide, and highly dependent on temperature (cold water takes much longer to act fully).

chelating approaches - Pur (a division of Procter and Gamble) makes a kit for 3rd world countries with poor sanitation that will collect the organisms in a flocculus (kind of a cottony looking mass) that settles, allowing decanting, as well as chelating a number of metal compounds and chemical contaminants. I have been doing a little testing of this.

Ultraviolet - Steripen is one example. The ultraviolet radiation kills most organisms. It does require fairly clear water (not as super clear as I had originally thought). It does not remove chemical contaminants.

In short, unless you are going to be on the rivers where there is lots of industrial and agricultural runoff for more than the occasional weekend, your Miniworks will be just fine. Actually your biggest risk is you and your companions not thoroughly washing and sterilizing your hands, water containers, and cook gear before food is handled. The studies in backcountry travel have shown that the vast majority (something like 80% or more) of backcountry illness is from improper food handling, not from the water. As your mother always told you - wash your hands before eating and after going to the bathroom.

I've used the Miniworks sucessfully in streams and lakes in Northern Michigan. You can find a brief discussion of the issue at REI.com, under their "Expert Advice" tab. Go to http://www.rei.com/learn/Camping and click on Water Filters/Purifiers. There, you will will read that viral contamination is not seen as a great hazard in the North American backcountry. Not the most scientific source, but close enough for me.

To be safest, you can always filter and then either boil or treat with chemicals.

Water filtration is one of the most discussed topics on backcountry websites. There is no shortage of websites that deal with water contamination and water treatments of the various types discussed above by Bill.

My suggestion is to start searching and reading as much as you can to get a good understanding of how to deal with water and possible contaminants.

If you do a Yahoo or Google search, you will find everything on the web from scientific papers, governmental studies, manufacturers's site to forums like this one that discuss water-borne illnesses, contaminants and treatment.

What you need, as Bill said, will depend on where you are and when. For example, last winter in Yosemite, I was melting snow for water, so I didn't worry at all about heavy metals, ag run off or similar contaminants. I was boiling the water as well, so that would have killed any bacteria or protozoa. Viruses aren't a concern where I was, as far as I know, so I did no further treatment.

My friends experienced what apparently was a stomach virus problem on a trip down to Venezuela this past spring. When they returned home the diagnosis was viral, not bacterial. I stayed healthy. Probably lucky. But I also tried minimizing exposure. Filtered the water first with a Sweetwater unit, then MIOX the water and let it rest for at least 6 hours before consuming. This was a windsurfing trip so mass and volume of gear was not an issue. Carrying an extra 8oz of insurance was worth it.

Any recommendations for a lightweight, compact water PURIFIER?

I also carry a water filter, the Katadyn Hiker Pro. It does filter out viruses but it doesn't mean it makes filter "useless." Your car windshield doesn't protect you against bullets and it certainly won't protect you against a sunburn on a hot day but it certainly doesn't mean it's useless. Water filters will filter out the biggest and most common stuff that can make you sick such as giardia, e.coli, and crypto which are common in areas where there are human and/or animal waste and other areas with contamination.

But you have to keep in minds that in most mountain areas of the United States and Canada the bodies of water are naturally free of most man made chemicals and viruses. In the Sierras I've drunk water straight from lakes and rivers and never gotten sick even in areas that see heavy human traffic such as merced river on the way back from Half Dome. I do have an above average stomach (or so friends say). There was an interesting article on the LA times about how backcountry waters REALLY are contaminated. The finding may surprise you: http://travel.latimes.com/articles/la-os-giardia26jul26

I have the Katadyn Hiker PRO and love it. I am of the school, no matter how clean the water looks, or how remote a scientist says the chance of getting sick is, a few ounces (11 oz to be exact) is worth its weight in gold. What would you do, 11 miles out, with a serious case of illness from a waterborne bacteria? What if you waited all year to hike Whitney (yes, I have my permit!) and halfway up you start cramping...we all know what comes next. (hint:it rhymes with flirts)

So, I will carry that extra 11 oz's and enjoy my relatively inexpensive insurance policy.

I found myself very concerned about viruses after an episode 8 years ago(likely non-viral contamination and likely my fault) had me laid up with beaver feaver for a week and then 2 months dealing with the side effects of Cipro.

I now double treat my water by combining Chlorine dioxide tablets with my MSR Miniworks. While you need to wait four hours for Chlorine dioxide to kill everything, it destroys viruses and bacteria in 15 minutes, Giardia in 30-minutes. (It is only the cryptosporidium that takes the full 4 hours)

I carry a (3 ounce wt, one gallon capacity) "Sea to Summit Little Sink" down to the stream to scoop up water and then carry it back to the camp area and drop in 4 tablets. Waiting only 30 minutes kills everything save for the cryptosporidium. I then filter the treated water through my Miniworks into a 2 liter MSR Dromedary bag and 1 qt Nalgene Cantene bladder. The activated carbon in the Miniworks takes away any flavor the chlorine dioxide leaves behind. The little bit of water left in the bag gets used later on for dish washing and hand washing with bio soap. I use the double treated water from the dromedary bag for dish rinsing.

This is borderline OCD I know, but I never want to deal with beaver fever or any fluoroquinolones again!