I know this has probably been addressed a thousand times here already, but I am new to the forum and just recently took up hiking again and would like to know the safest "modern" methods to use. Years ago I just used iodine tablets to purify water from streams, but have heard recently about filters and ultraviolet pens and all sorts of things that I am unfamiliar with. Any help would be greatly appreciated. Thanks! <img src="/forums/images/graemlins/confused.gif" alt="" />

Welcome to the board and welcome back to backpacking! Hope you have lots of fun.

As I understand it the real concern over water treatment among backpackers began in the 80s. The most common DIY water treatment previous to that was to carry a little sodium hypochlorite (bleach) which would kill bacteria. And even taking this precaution was a little uncommon.

Then a study came out which indicated that almost all surface water in is contaminated with Giardia. Giardia is a cyst, not a bacteria, and is one of the leading causes of severe diarrhea among humans. Giardia is a spread through contaminated fecal matter. Beavers can also get Giardia and so they were often blamed.

The problem with Giardia is that it is completely impervious to hypochlorite and somewhat resistant to iodine (another common water treatment) as well (it will work but it takes a long time to get the desired results). Another cyst, Cyptosporidium, is very resistant to iodine.

Fortunately cysts like Giardia and Cryptosporidium are quite large compared to bacteria and other microorganisms. So a good filter can remove them from water. Soon filters were considered required gear for hikers. Many good brands of these.

Chemicals exist which are more effective against cysts than hypochlorite or iodine like chlorine dioxide (Aqua Mira is one brand of this).

UV light will inactivate all microorganisms (including cysts like Giardia) by scrambling their DNA so that they can't reproduce. Steripen is a gizmo which does this.

If using chlorine dioxide, iodine, or UV light you will probably want to do some filtering beforehand just to remove junk you can see. Bandanas or coffee filters are often used for this purpose.

However things have now come full circle and people are beginning to wonder if the fear of Giardia hasn't been overblown. First of all it seems that although all rivers and streams are contaminated the levels of contamination are often less then or equal to city water. Secondly it seems the beaver has been falsely accused. It now seems that they are the victims. Giardia is very common among humans and many people are carrying it without knowing it (there aren't always symptoms). Furthermore Giardia cannot survive for months in frozen streams and lakes. So it now seems more likely that people who carry Giardia re-infect the surface water every year by defecating too close to water sources. But the infected water sources are now thought to not be the most direct or most likely way to get Giardia from other hikers. It seems likely that most Giardia is spread by hand-to-hand contact with a hiking buddy who didn't wash his hands properly after defecating.

So it's another case of "everything I need to know I learned in Kindergarten". Wash your hands often: after each "call of nature" and before eating. That will keep down hiker-to-hiker infection. You may want to filter or treat your water as well to be on the safe side. However many hikers don't treat their water at all and they don't seem to have a greater incidence of Giardia than other hikers. Make your own decision in this regard.

Hope this helps.

Heber, thanks a million for your detailed response. Last time I really hiked was in the early 90's, and all of my experience has been in the Great Smokey Mountains National Park and around Mt. Cheaha in Alabama. I was told then that iodine tablets would cure everything, and I guess they did. But I was a teenager then in great shape, and now I'm in my thirties and hoping to get back into SOME kind of shape besides round <img src="/forums/images/graemlins/tongue.gif" alt="" />. I'm not as fearless as I once was and from what you've told me I think I should get either a filter or a UV pen. My wife is going hiking with me and I don't want to just go without any safeguards on the trail. I have a friend who hikes a good bit and uses a filter, but the UV pen sounds tempting since you say it sterilizes ALL microbes. I don't mind consuming them as long as they can't procreate inside me. I would still appreciate any recommendations from anyone on good filters, since I'm several weeks away from my first hike and have time to shop around. Anyone who knows a good website that sell any of these systems, I would love to hear from ya. Again, thanks Heber!!!

Always a pleasure to help someone else trying to get back into hiking! I'm just the same. Did a lot as a kid and I've only been back at it for a year or so.

I have the UV pen (Steripen Adventurer). I get a kick out it. It's cool because it takes no effort. However there is a downside. Because it runs on batteries you can have problems. Some people have reported that theirs failed them. A few of us have also noticed that if you leave the batteries in the pen then they slowly discharge. As long as I charge mine before each trip and take the batteries out in between uses it works fine for me. But YMMV.

As far as filters go the ones I hear the most about are the Katadyn filters made my PUR (these have been popular with hikers for years) and the MSR filters like the sweetwater filter or the new hyperflow. Some people really like filters because it's a one step process and you can use any water you find (with chemicals or UV you have to do some straining with a cloth first or look for water that is pretty clear already). I don't like filters because I find they take a lot of effort to use and it gets progressively harder with use until you change the filter element. But to each his own.

All of these (both filters and steripens) are available at rei.com but there are probably other sites where you can get them.

Campmor.com
SierraTradingPost.com (known at STP here)
and vendors accessed through the TLB portal at the top of this page (helps support these forums)