View Full Version : Filter or No?

02-07-2003, 14:09
New to the forum. Thanks to everyone for some great information. Question... I already own a PUR Hiker (from a few years ago) that weighs in at 12 ounces. What are my other options for purification and what are the associated weights, cost, and taste? I'm trying to decide if there is a lighter inexpensive option for my thru hike.

02-07-2003, 14:24
Hi Wilson76,

Welcome to the forum and keep checking it out for all the information that is available here. I don't think you will be disappointed, just keep in mind that we are all different and each person may do things a little differently than someone else. Not that either is wrong in how they do it, but what works for some may not be the best for others.

Now to get to your question, I also used a Pur Hiker for half of my thru hike in 99. However, I did switch to the Aqua Mira and have finished about half of the AT with just using it. I still have not gone back to the filter, even after 3 years. For me the Aqua Mira is by the best choice. A lot of people still carry the filter and that is their choice, others go with iodine treatment, which is actually lighter than the Aqua Mira since it is just one small tablet. Basically it is a personal choice, and if the weight of carrying a filter is not a problem, then take it. If you want the lightest weight, it would be the iodine tablets, but I can't stand the taste of those, so that is why I use the Aqua Mira. So it all boils down to what you are willing to carry and if it will work for you.

Hope this helps.. and I am sure you will get a lot of different responses. Just do what is best for you and you can always change in route if you desire.


02-07-2003, 14:27
Oh my God did you just open Pandora's Box! A lot of disagreement on this topic. Many Thru-hikers either use a filter or use some sort of chemical to treat all water. Many use the above to treat the sources they feel are sketchy. Others treat absolutely nothing. I think statictically people who treat and don't treat have the same chance of being sick.

My philosophy is that there a lots of stuff out there that hinder and prevent one from thru-hiking. If you can control one of those things then do it. I carried a filter or Polar Pure the whole. I switched to filter when water became more scarce and harder to retrieve during a dry year. Did not get sick. However SGT Rock pointed out on an earlier thread that the effectiveness of filters goes downhill in environments like the AT - overusage. Who knows why or why not I did not get sick.

It comes down on to what you want to carry. Are you affraid of water sources? Is 12oz too heavy or would you rather carry 3oz bottle of Polar Pure? IS taking that much Iodine a little sketchy to you?

Lone Wolf
02-07-2003, 15:21
Some hikers don't filter or treat any water at all. I'm one of them.

02-07-2003, 15:43
There are also some great comments about this subject located on this site at this link:


Lone Wolf...that is kind of an UNDERSTATEMENT isn't it?
:D :D :D :D
How many years have you been not filtering, how many miles????

02-07-2003, 15:52
Thanks for the input now some follow-up Q & As. I have used the filter on all my backpacking trips and have been happy, but these consisted of mostly 3 - 7 days trips. I plan to continue to treat water in one way shape or form. For my thru hike I want the eaiest, lightest, best tasting option. I guess I want it all! I see my options as...
Filter - a little heavy but will only cost the price of replacement filters
Iodine - don't think I'll like the taste but definitely a lightweight option
Polar Pure or similar - sounds intriguing but how much are those tablets going to cost me for a thru hike?


SGT Rock
02-07-2003, 16:20
Polar pure is iodine crystals that you add water to to make the solution. Less iodine taste than the tablets and one bottle would last a whole thru-hiker. The tablets are stronger and one bottle would last about a week or so, maybe two. The tablets weigh about 1 ounce, the polar pure weighs about 3 ounces - 4 with the water in it.

02-07-2003, 17:52
2 thumbs up on Polar Pur. I sent my Pur Hiker filter home at Neels Gap and changed over to Polar Pur. That bottle made it all the way to Special K and I'm still using it. Suggest you check with your doctor about long-term iodine use.

Regarding not treating water... Many times I chose not to filter and drank straight from the source. Especially piped springs. Awesome! That was a personal decision/chance based on many years spent outdoors. I was not betrayed...

02-07-2003, 20:32
There is a book by Roland Mueser called "Long-Distance Hiking: Lessons from the Appalachian Trail" that contains some very interesting data on water treatment, along with many other topics as well. He got surveys from 136 hikers back in the early 90's.

To make a long story short, what he found was that there was NO correlation between frequency of water purification (by whatever method) and incidence of gastrointestinal illness, including giardia. In fact, the people who "always" or "never" purified had a lower incidence of illness than those who "usually" or "sometimes" purified. Certainly a stunning result.

Mueser argues that this is not a problem of small sample size. The 136 hikers represent about 15,000 person-days of backpacking during which hikers sampled about 1,000 water sources, with each hiker "testing" several hundred sources in the course of the hike.

His theory, admittedly unproven, is that GI illness has more to do with personal hygiene, dirty cooking gear and sharing of food and utensils. Did you ever let someone else put their hand in your gorp bag? Maybe not a smart move. There is some data cited that says that about 4% of the population are asymptomatic carriers of giardia. As Muser says, the picture of innocent hikers being infected by the water supplyu

For myself, I have migrated to using Aqua Mira for the larger in-camp volumes of water. On the trail, I am using the Exstream bottle filter, which lets me dip and go. I don't like to stop and take off my pack. More importantly, I will wash my hands after every bowel movement and before doing any food preparation. I very much agree with a previous post, that there are enough uncontrollable hazards in a thru-hike that I am going to at least try to control the ones that I can, so I will treat all water and do the other things also.

There is no filter that will remove viruses, they are just too small, only chemical treatment or boiling will kill them. However, from what I have read viruses are not a concern in the North American backcountry. If I were in a third world city, I certainly would be concerned.

Pete Hoffman

02-07-2003, 20:37
Sorry. I posted without reviewing.

The corrected line should read.

As Mueser says, the picture of innocent hikers being infected by the water supply may well be backward: It could be that the hikers are the source of contamination.

Pete Hoffman

02-07-2003, 23:04
The cost of replaceing Pur filters is high, but their life can be stretched by wrapping a coffee filter around the pre-filter. Also you can get one of those slick sylnylon water bags and alow the silt in muddy water settle. Where water is clear, I plan to just use iodine. I'm not sure why, though, I've been drinking radium for 26 years...

02-08-2003, 10:38

We used the Pur Hiker the entire trip. For two people filtering about 6 liters of water a day, we replaced the filter cartridge onlythree times from Georgia to Maine. Our main reasoning for using the filter was becuase we trusted it, had used it often, and found we could eliminate a few ounces by getting rid of that heavy plastic filter cover knob on the end, the special naglene adapter, etc. We also wrapped coffee filters around the intake and it siginficantly increased the life of the filter.

I have said in another post but it bears repeating that there were quite few times on the trail when the water source looked questionable at best, and we ended up lending out our filter to the folks in our group who had only Aqua Mira and Polar Pur for purification. This was especially the case as we came north, and always the case in New York and NJ :)To drive the point home for us, we were at one shelter where someone picked up their platpus hydration system and clinging to the inside were teeny, tiny leeches. One look at that and I couldn't help but exclaim "THANK GOD I filter my water.:) Just something to think about.

02-08-2003, 15:46
The posts above sure cover the issue concerning the need to do something, but something I didn't read was the criteria to make iodine, chlorine dioxide, or any other chemical truly effective...and that is the condition of the water to be treated.

Temperature, cloudiness or turbidity, pH, and organic content all have an affect on how long it takes to properly treat water. Contact time is substantially increased with cold water...and that's when I like to drink it! Cysts such as Giardia, Crypto and Microsporidium are highly resistant to chemical kill. On the other hand a filter with a 1 micron absolute removes them, but caution must taken to use your filter correctly lest you contaminate your filter.

I've read the Center for Disease Control reports and they say Giardiasis is on the increase, Vermont leading the way with reported incidents. The PA Game News reports not one river, lake...(all man made in PA), or stream is free of Giardia contamination.

Bottom line for me is filter the water. Chemical disinfection is more of a roulette game unless your very picky about what your doing. I've had Giardia once, picked up from a state park that supposed added chlorine to its water, never again!

02-10-2003, 11:36
Any thoughts on the Katadyn Orinoco Water Purifier ?


Pluses seem to be that it is lightweight, no moving parts, and initially inexpensive.

On the other hand if one filters everything replacement filters may end up costing about $150 over the course of a thru hike.

Has anyone had any experience with these type of purifiers?

02-10-2003, 17:45
Pur, and now Kataydin, guarantees their cartridges for a year. So, there is no need to pay for a replacement during your thru-hike.

Most outfitters along the trail will exchange your cartridge for free, no questions asked.

02-11-2003, 10:25
St Rock or others can you please give me more information about Polar Pur? Where to get, how to use it, etc. I did a google.com searhc and came up dry!

SGT Rock
02-11-2003, 10:36
here you go: http://www.campmor.com/webapp/commerce/command/ProductDisplay?prmenbr=226&prrfnbr=13879

It is basically iodine crystals in a glass bottle with a neck that keeps the iodine crystals in.

1. You add water into the bottle. The water saturates to it's maximum capacity based on the water temp of the water in the bottle.

2. Fill your water bladder or bottle. If you are offended by chunks, use a bandana or coffee filter. Chunks taste good BTW.

3. Look on the temp indicator on the bottle. It lets you know how many caps from the bottle to fill with the iodine solution per liter/quart.

4. Add the solution as indicated by the bottle.

5. Wait 30 minutes and water is ready.

My technique is to fill my bottle with treated and cured water, and fill my bladder with another liter at the start of the day. When I stop for water (at brunch/lunch/dinner), drink my bottle completly while I fill up and cure 3 liters. After 30 minutes I have another liter to drink, then fill my bottle, while another liter stays in the bladder. This way I always start walking with 2 liters and camel up with a couple of liters. When I stop at night I treat 3 liters before cooking (plus my liter bottle). That gives me a liter for dinner, a liter for breakfast, and my two liters for starting in the morning.

One bottle does 2,000 quarts. That is 500 gallons. On a 6 month thru hike, you could drink 3 galons a day of treated water and still not run out.

02-11-2003, 11:24
Once again there is proof that none of us is as smart as all of us... thanks so much!

How about muddy water etc??? If the season is dry I may be looking at shallow water sources?!

SGT Rock
02-11-2003, 11:40
I drink it anyway

02-16-2003, 18:29

Good point about the water condition. The back of the Aqua Mira package says that if the water is very cold or turbid that the water should be treated for 30 minutes before drinking rather than 15 minutes. I will also take to heart the comment that Jumpstart made about the beasties in the water and do a gross filtering (coffee filter, bandana).

You obviously had a bad experience with the giardia. My question, however, is how did you know you got it from the water supply? Were you at the state park with others? Did you share food and/or utensils?

The information about Vermont being the leading giardia state is not new. Mueser mentions that in his book. (see previous post) He also talks about how it is not possible to get a meaningful answer on giardia in a water supply by filling a small bottle and sending it off to the laboratory. Testing of public water supplies are "carried out over the better part of a year and involve many samples taken from hundreds of gallons of water."

It makes it sound like the Pennsylvania Game commission is simply doing a CYA. They are - you should pardon the expression - washing their hands of any responsibility.

Don't misunderstand. I am still going to treat my water, I am just not going to be paranoid about it. What I am going to be paranoid about is personal hygiene, not sharing, and cleaning utensils.

Pete Hoffman

02-16-2003, 19:48
I'm sure it was the water. I'm meticulous about eating habits, sharing food, and filtering water. My MSR ceramic filter is carefully stowed in my pack and gets boiled when I get home.

It takes two weeks or so for the symptoms to surface...the critters have to build critical mass. I could track back to that time.

Might be right about the PA Game News, but I've heard this before from other sources as well.

Being in the water treatment business, I've been amazed what some will risk when known bacterium or cysts are detected or most probable. Effective chemical kill is subject to many variables, more so than with properly handled filters. I'll carry the weight for the peace of mind.

jimmy b
02-20-2003, 21:58
water filter or polar pure, i carried a msr water filter to Great Barrington, Mass. and I needed to replace the water filter because it had stopped and before that it was taking half an hour sometimes to filter a quart. Instead of replacing the filter which I could have, because I found one in a outfitter, I switched to polar pure, I didn't have any problems and the process is much faster and the weight is only 3 or 4 ounces.

jimmy b

02-21-2003, 00:28
If you do not like the taste of iodine...treat it as you normally would, i.e. let the iodine do it's work. When it is ready to drink, use your pocket knife to shave off just a bit from a vitamin C pill, close the lid on your water bottle, shake, and poof! Brown color is gone and no iodine taste at all.
The company that makes the little iodine tablets sells a style that has two little glass bottles....one is the normal iodine and one is the "taste remover." Read the label on it...it is just ascorbic acid, otherwise known as vitamin C and they charge you like $10 for this "kit." Cheaper to just go get some vitamin C pills and do it on your own. One large vitamin C pill would last me for at least 500 miles or more.

Works like a charm. :)

02-22-2003, 05:27
In general water along the AT is not infected, and as long as you use common sense you shouldn't get sick. I only treat about 30-40% of my water and have never gotten sick, although I'm sure others have. A water filter is kinda pointless, especially a "purifier" as there are no viruses in North American water. Giardia is very rare.

02-22-2003, 09:38
Commercial filters can clog with no warning (as did my First Need Water Purifier). Sometimes backwashing can help, but usually has little effect (such as with my First Need). In some cases gravity filtration will still work, but not all (as with my First Need). With fiberglass-type filters (First Need, Katadyn Hiker) your stuck. With ceramic filters (Katadyn & MSR) you can scrub the grimy slimy bacteria, cyst, and virus laden gruel from the filter surface, often chancing infection by cleaning! Ceramic filters also crack when residual water freezes within them. Filter cartridges (ceramic & fiberglass) can also develop short circuits from continued use, over pressurization, backflushing, freeze-expansion of water, and simple defects. In short I don't trust or use them. They also tend to weigh 11-25oz, even more when carrying a backup cartridge. Oh yeah, the only stand-alone filter that removes virus without chemical useage is the First Need. With all the others you take a chance.

You can also go the all-chemical route. Iodine tastes nasty to me, and does nothing against virus' from what I know. Chlorine can lose it's effectiveness if not properly stored, and has a short shelf life even then. Chlorine dioxide (aquamira) has a long-shelf life, little/no after taste, and weighs only 3oz a set, even less as you use up the fluid. It also costs the most at $13 a set for 30 gallons of treatment. Some pretreat with a coffee filter, which is very smart because quite often the chemicals you treat with cannot penetrate clumps of material (by clumps I mean small pinhead size bits).

Then there is the grizzly adams method of drinking untreated water. You obviously roll the dice using this method, but you can stack your odds by educated decisions on what sources are worthy of this method. In heavy farm land areas like vermont, this is often a risky method.

I use a hybrid method. A stripped down pump and hosing to draw water from tough/deep sources, and attatched is a SiltStopper 2 Pre-Filter which removes dirt, algae, and large foreign media, and some of the larger cysts. I then treat with Aquamira to eliminate all baddies and some of the color/taste issues.

The pump, hosing, Siltstopper pre-filter, 3 replacement filters, Aquamira, and stuffsack weigh 10.25oz.

Oh yeah, you can also boil your water. During the winter this is all I do. Saves you filter/chemical weight, and most of the time you have to melt snow anyways. During warmer months where liquid water is available, this method is too heavy to use.

I'm also going to copy this and keep it on hand for pasting for the next time a new memeber opens pandoras box.... :D :banana

02-22-2003, 09:59
...there are no viruses in North American water

Not true. I am a wastewater treatment operator in Massachusetts, and we treat our water to remove cystic, bacterial, and viral pathogens. For one example, some types of Hepatitis can be transmitted through contaminated water. Hepatitis can be a lethal infection. We saturate & detain our water with chlorine gas to accomplish this.

In worst case scenarios, I'll boil my water and eat crunchy rice over not-treating at all. Even fountain like springs, as downhill leechnig can contaminate the source. Just my thoughts.

02-22-2003, 11:05
RagingHamster ...want your opinion on something, since you're somewhat of a water treatment officianado. I'm using a water filtering/purification system this year not too dissimilar from yours. However, instead of the SiltStopper 2 Pre-Filter though I was planning on using the little screen element that came with the old PUR Hiker filters that fits inside the black acorn. Over that screen I was going to place a coffee filter for added sediment removal. Then I was going to either boil for a meal or treat with AquaMira.
I know it's not going to get me the 5 micron filtration of the SiltStopper 2 Pre-Filter but is lighter and wouldn't need to be cleaned or replaced.
Whatayathink ??

02-22-2003, 12:34
I would like to point out that I'm not trying to scare people. Unless your drinkning from cess pools, or water located in farmed valleys, you have a very small chance of getting an infection. Still, much of the land on the AT in my area passes through areas of farming and grazing fields. Be very careful of where you get your water.

Last september, I was hiking an 8 mile loop up and around Stratton Mountain in southern Vermont. I brought a half gallon of water with me, and foolishly should have brought more as the temps rose into the 90's. I ran out of water about 4miles later (I drink alot), and ended up sponging off from my friend who carried extra. I was tempted to drink from the two springs I passed, but was glad I did not as the caretaker on the summit told me there were 2 cases of Giardia they thought came from this area (from section hikers who reported they had Giardia).

I'm actually not sure about the "pore" size of a coffee filter if youd call it that. Youll also need some type of funnel to fill your water containers if you go the coffee filter route, or pour the water real slow. On my setup, I had the pre-filter from my First Need setup on my new setup, but discarded it, as most of the time the water I filter is relatively free of large debris. So now I just use the 1oz siltstopper w/3 replacements that weigh in at 1oz together. The real heavy portion of my setup is the pump mechanism itself. I'm currently looking for a lighterweight pump, which would cut the weight of the system by 2 or 3 ounces. For my water containers I use two 3L platypus dromedary bags (2.75oz together) and a 1.75oz 1L widemouth pepsi bottle, giving me a 7L potential capacity which is plenty. I prefilter the water into the platypus bags, and only chemically treat what I drink from the pepsi bottle. My cooking water is always brought to a full-boil to kill any nasties in the water, or residing on my pot/utensils.

I'd also like to point out that most commercial filters retain water making them even heavier, and that almost all tap water is treated chemically, with simple screening of it's source.

There is also another method I forgot to point out in my last post, UV radiation. But the current "pen" style models are delicate, heavy, require batteries, and only treat small volumes at a time. However as this method gets more research and funding, it may become practical for backpackers. For now I'm sticking with the method our states and towns use, pre-screening and chemical treatment.

02-23-2003, 01:15
Fair enough Hampster....and I have heard of some very rare cases of Hepatitus being found in water. I actually heard of a case in Duchess County in NY about 9 years ago, but I don't think you will find viruses in mountain springs or ground water. I think it's safe to say it's not worrying about. But compared to some other countries you don't have much to worry about along the AT.

warren doyle
09-22-2003, 10:28
26,000 miles of walking on the AT. I have not filtered or purified. I consider giardia as a gift that the trail has given me.
"If the human species has lost its animal strength, perhaps its individual members can have the fun of finding it again."

10-07-2003, 00:21
The side of the AquaMira bottle also says their product should not be ingested nor is it guaranteed to be reliable. Gotta wonder about a product such as that.... *rolling eyes*

For what it's worth, I *almost* never purified or filtered any water sources I drank from and never so much as got a cold during my entire thru-hike. I did carry some AquaMira just in case I was "forced" to drink from a water source I had serious doubts about, which I ultimately did do--once in Massachusetts (or was it Connecticut?), and three times in Maine.

Most of the water I used for cooking purposes ultimately was boiled in the process which might have helped too, although I didn't boil the water specifically for that purpose. Just a bonus.

On another note, because I wasn't treating my water in any way, I was probably much more selective about the water sources I drank from than most other hikers. I'd deliberately stock up an entire day's worth of water if I found a great spring even if it meant carrying more weight while other hikers would carry less water but resupply more often--from less reputable sources.

I can't say I'd really "recommend" not treating your water. If you feel safer doing so, by all means, you should do it! Being able to sleep without worries is important! But it is an option. And you know, sometimes it feels great just to scoop out a bottle of water and drink. No messing around with filters. No waiting for chemicals to do their thing. Dip and drink. Instant gratification, and it was absolutely wonderful much of the time. =)

Carpe diem!

-- Green Turtle, thru-hiker 2003

10-07-2003, 07:42
Before you decide to not treat your water, remember that people who have had a good case of giardia say that giardia will not kill you, but you will wish it did. Is it worth the risk?

10-07-2003, 08:40
I think the Aqua Mira warning has something to do with the state of California not having certified chlorine dioxide as a safe, reliable method of treating water. I think Potable Aqua used to also indicate that it should not be taken internally.

10-09-2003, 10:03
During my 03 thru-hike and every trip before that, I have used bleach to purify my water. Works great, doesn't taste horrible, and is cheap, light and easy to find. That said, I didn't use anything many times up north and I'm telling you, nothing tastes better than fresh mountain water :)

10-09-2003, 15:23
According to some sources, household bleech isn't all that effective. Obviously, it worked for you, but I wouldn't recommend it to others

bearbag hanger
10-11-2003, 09:46
I use a filter now. The problem with the iodine, etc. tablets, for me at least, is they can create some health problems, particularly if taken over a six month period. But I guess Sgt Rock has done this for longer periods without problems, so again, it's an individule decision.