View Full Version : Who Filters, Who Does Not Filter
I am truly wondering about this since I seem to be reading more and more articles with substantial evidence that the incidence of contracting giardia from fast moving water sources and springs is statistically quite remote. So with all the miles hiked on THIS board I'm very interested in the results of this poll and who does what and why.
For the past 4 years, I've treated everything that I don't boil, except when I'm up north, where it would be some sort of soulhurting crime to treat the beautiful water. This summer, however, I am planning on only treating occasionally, and then only from sources that look a bit dodgy.
I filter or treat everything. When water is plentifull and clean I'll just use iodine. When water is nasty and stagnant I'll filter.
I generally treat all my water these days. But in the 70s and early 80s, everyone drank straight from the streams. I only got sick once from doing this, and that was during a heavy 2 day rainstorm when the ground saturated and streamwater was direct ground runoff.
Out of 1800 plus miles I treated only 3 times. Never even got the slightest bit sick.
It's not for everybody. However, I knew more "sick" filter users then non.
I remember those days Deb...all I took to hike was a sierra cup and small canteen and drank water from any source, (well except for that nasty run-off from the Mt. Washington summit facilities).
I do admit to not filtering from ALL spring sources and MOST fast moving water, but then again I'm kind of live a sheltered existance here in NH....hopefully that will change soon.
Interesting to note:
I know there is one person on this board who has been hiking the AT for the past 16 years and does not filter, (I read about it on another board) and has suffered no ill effects, (which initially got me to think about this very seriously and after looking into it I found even more to support his experience, that's one hell of a lot of miles so as I said it truly got me thinking.)
BTW...was the source that you filtered really nasty looking, as in mudhole???
Maybe I'm just paranoid. Then again we occasionally get letters from the government declareing our municipal water unfit to drink, too much radium. Oh yeah, and pregnant women should not eat fish out of the Illinois river. I love my industrial wasteland!
Used a filter until 2001. Have both the MSR miniworks and the PUR Hiker. For a while I carried PolarPure in addition to the filters and sometimes only treated with iodine. Then I discovered AquaMira and haven't filtered since. I have yet (with or without a filter) been subject to any physical problems from water. For this years thru I am considering the use of a small pump with a particle strainer, when the water supply is too small/shallow to allow for scooping of water with a cup or nalgene.
My wife got something NASTY as I have posted on here before. She had tons of tests, but they never found anything. But she was rushing into the woods about every hour, sometimes she could barely get into the woods.
We started treating with Iodine, then we pretty much quit after a week. I never got anything.
Apparently the big G various from person to person. I have heard some pretty outlandish urban (or should I say aborial) myths about people being found competely insane at shelters from dehyration from this. I have a hard time believing those. But on doing some research, they guesstimate about 1/2 of all people will never get a bad reation to G, some will get it REALLY bad.
I treated twice in VA when I was basically camped in Cow fields. I treated once in VT when I was taking water from a beaver pond.
I unknowingly drank water in NH that was a beaver pond run off and was fine.
I had a problem in MD when all the water holes I pasted in 7 miles were mudholes. Never ran out but had to ration for awhile.
Even last summer when it was so dry I was always able to get water. Sime stretches were longer then others, but those with filters were having the same troubles.
GA-NJ I used a PUR Hiker which would clog every few weeks or so. NJ-ME I carried an eyedropper of chlorine. Weight: 1lb vs 2 oz. Never have been sick. I treat most of my water if I have the time. I believe that most of your gastrointestinal ailments result from not washing your hands after visiting the privy and heading straight to cooking mac and cheese for the night.
Everyone has different levels of tolerance to Giardia. It takes a few things to go wrong in order to get sick. You can find a lot of science journals on this topic over at www.pubmed.com
I used a filter on my first hike, and Poar Pure my last six. I drink water straight at least half the time, and have NEVER goten sick. It's ultimately a matter of judgment and common sense, depending on where you are and what the source happens to be.
The giardia threat, in my opinion, is greatly exaggerated.
Well, we have been over this topic before. I'll agree that giardia gets blammed for everything, when it's most likely lack of basic hygene. But, people that have had a good case of it tell me that it may not kill you, but you wish it did. So, is the risk really worth it?
Jack, just because you didn't get sick doesn't mean you didn't contract giargia. It just means that it doesn't make you significantly sick.
Some people have a very bad reaction. Others, nothing... and by others, I've read it's about 1/2 the people that aren't affected. So keep that in mind when you suggest to people that they don't need to treat.
YMMV (Your mileage may vary)
Never treated water.. ever. Of course, I did get Giardia (ONCE), but it wasn't that big of a deal for me. I just wish I had known the symptoms since I hiked with it for a month. Everyone I know told me that I would not be able to walk, I would be violently ill, etc..
In actuality, my energy level slowly dropped to the point that hiking 13 miles was a problem. I also had bad reactions to beer and ice cream. As a result of having the disease for so long I can no longer drink milk, but I was slighly lactose intollerant to begin with.
Pretty picture - no, not really, depending on your point of view. Philosophlically, I just cant filter water. Yes, I carry a stove and high-tech clothing, blah, blah.. but drinking purE water is for me just part of backpacking. Hunting around for water in Zion was interesting, and it was quite muddy. I have soaked up water with a bandana and squeezed it into a water bottle. I carry a straw so that I can slip water from a thin puddle.
The problem with filtering EVERYTHING is that, if you are that worried about nasties, you really need to be paranoid. First, you need to make sure that the "dirty" end of your filter never touches anything else. Then you need to make sure that you wash your hands constantly, and never shake hands with another hiker. (or go promptly wash yours again.) You can never take a sip of someone elses water, touch their packs, eat their food, etc... The reason here is that the other person is an unknown, they might have contaminated something of theirs with a disease. Also, you cannot bath in a river if you have any kind of open wounds. This includes SCRATCHES and popped BLISTERS - diseases and whatnot can slide right in through your blood stream easier than taking a gulp of water into your gut. Also, you can NEVER wash your face in a stream or a river. If you do that, undoubtedly some of that water will trickle into your mouth, and it only takes three spores of giardia to blah, blah, blah......
See my point? Once you start filtering everything and becoming suspect of EVERYTHING, you need to follow that suspision to its logical conclusion. I choose to go the complete and total opposite direction and not worry about anything. Just IMHO...
And FWIW, I have done some extensive research on Giardia and it does effect different people differently. I have read that from anywhere from 1/2 to 4/5 of the people that contract giardia never show any symptoms - and those that do are often mild (like me). The most common way to contract giardia is fecal-oral, or in other words shaking the hand of some with giardia (with bad hygene) and then going to east a meal. For 99% of the giardai cases, the virus enters your small intestines, set up shop, produce MORE giardia (inactive) spores or whatever, and then die. Gone, kaput, fini sans medication. There is a small percentage of people, tho, that do contract chronic giardia, but the percentage is so low that not much info is available. IMHO - Lyme disease is a much more real and much more serious threat to worry about.
I am often berated for trying to go so light that I won't carry a filter. First let me say as I always say: Free Drinking is not for everybody. That said, I don't omit the filter for weight. I omit the filter because I don't feel I need one. I use to carry one many many years ago. It broke on so many trips and I always made it out okay. I just stopped carrying it. Like I said I have been drinking the water w/o filtering for years. Perhaps I have built up an immunity, perhaps I am a carrier... Who knows, but it works for me. I figure it is a fifty fifty gamble, one I am willing to take. On the flip side my husband wouldn't think of drinking unfiltered water. To each his own. Hammock Hanger
I've been hiking for over 30 years (well backpacking for about 25) and used a filter on two trips, hated it and tossed it. Before Istarted, many people hiked and never needed them.
IMHO a filter is a confidence trick. You buy it because you belive it helps you, not because it actually does. Read Roland Mussler's book "Long Distance Hiking: Lessons Learned From the Appalachian Trail" and find that the filter users have about the same probability of getting sick as someone that doesn't filter or treat. It also has some good lab data showing that a filter gets less protective over a few uses than treating which is consistant with whatever technique of use you go with evey time you use it.
I never remember anyone using filters before I went off to basic training in the 80's, but returning to the AT to hike in the 90's I found many people using them and swearing it was what they needed to stay safe. I think it is good advertising by the manufacturers mostly.
I have never filtered or treated water on the AT. Never been sick.
The need to filter water varies with individuals. I was a Boy Scout scoutmaster for 14 years and I kept a journal of every trip we went on. Our troop is from a rural area and some of the boys came from the "city" (population 2500) and some from the "country." The "city" scouts of course drank treated water at home from the local water supply while the "country" scouts water at home came from private wells drilled on their property. Without fail it was always the "city" scouts (or dads) who had the stomach problems which was ultimately blamed on untreated water. Looking back through my notes, I cannot find a single case where a "country" scout had any intestinal disorders while on the trail. So I believe the "country" scouts had built up an immunity to the Giardia bug by drinking the untreated well water. It was such a problem that we started treating all water and almost eliminated problem. Of course the change in food, its preparation, cleanliness etc could have played a part in the original problem.
Even rural parts of the country have "city" water available now and well water is becoming a thing of the past. Most troops now filter all water, in mostly a CYA mode, whether it is questionable or not.
It's a common sense thing with me, if I question the water source, I filter or use Polar Pure / Iodine tablets. Chris is right, there are some water sources where it would be almost blasphemy to filter or purify. When you're at one of those places, drink up and enjoy!
As many of you have mentioned there is a great deal of variability on who gets sick and who dosen't. I have read studies that alot depends on the flora and funa that exists in your stomach. If there are alot of good, healthy bacteria there, you can take in alot of "bad" bacteria, be it food or water, and the "good" bacteria fight them off. To keep the "good" bacteria healthy eat a lot of yogert (I know it took me a while to get used to it) or take a probiotic such a Fruitafit. I have given this to people who go to India for business and always get sick even when thy do not drink the water. It has worked for them. I still filter, but I think probiotics is more of the reason why I don't get sick.
I always filter. Having had food poisoning in the past, an intestinal disorder is something that I will avoid at all costs. I think it would be better to be dead than suffer like that for an extended period of time.
Another big motivator for me to filter is watching the various activities that generally take place "upstream." And, there always seems to be an upstream, no matter how high in the mountains you get. Horses are taking dumps as they cross the stream. A variety of other animals are doing the same. Not very appetizing.
But, like everyone says, it seems like different body types have a different level of tolerance for it. Apparently, my tolerance isn't very high. Then again, all my life, I drink treated, fresh and tasty Lake Michigan water. Outstanding!
I filter or boil everytime....got a good case of heliobacter Pylori a few years back ..was out on the desert of s. cal. and drank some water from a well that had been contaimated during some flood rains.....boy I was I sick...hospitalized...Diaherra on the trail is not the way to go...you loose body fluids and then it is hard of not impossible to drink enough fluid to repalce what you are lossing and hike the trail too...ONCE IS ENOUGH..
take immodium with you in your first aid kit ..it could save you a**..
I don't think anyone is suggesting that you drink water from just any stream. I always drink untreated from a spring but use polar pure on questionable sources. If you are at the very top of the mountain your chances for problems would be less that at the bottom. It' supposed to be an adventure.:)
As a great AT hiker once said after his 3rd bout of Giardia, "Giardia isn't a big deal as long as you have a good book and a clean bathroom".
a use for wingfoots after all....
I filter mostly. Before filters were cool, I treated all water. I agree with Uncle Wayne...I am a city boy, I filter my city water because I don't like the taste. I drink a lot of water (>3 l) every day. I, like illininagel, have had food poisoning and don't want any thing similar ever again. Like the Sgt. said it may just be in my mind, but not worrying about the water improves my trip. I also wash my hands frequently, and carry the extra weight of hand sanitizer...enough to share with my hiking partner.
weeknd ..me too on the hand sanitizier...
top of the source ..right ..
hang around a spring for some time and stay out of sight and very quite...and see what kind of activities happen there..right at the source...
Iv'e watched birds bathe and ***** right in the spring ..right on top of the hill...
Down by the spring on a Hollow Log ..
shell of a crawfish ...
bones of a frog...
late last night,,
by the Dark of the Moon..
down by the spring...
It was Mr. Raccon...
It starts with an S..
and ends with a T...
Where is the logic of being paranoid about the water you drink but not hesitating soaking one's blistered, tattered feet in a stream? This seems like a better way to pick up an unwanted parasite since an open blister has no defense mechanisms, unlike a stomach.:-?
I think we're coming full circle on this thread. There seems to be plenty of living evidence to support just about every approach mentioned here. Each of us just has to do what we think is best and accept the associated risks.
Just my .02
The parasites that we are worried about are the ones that have adapted themselves to live in the digestive system. They can't live anywhere else, like a cut or a blister. Cuts and blisters will most likely get infected by bacteria. Bacteria is everywhere, but only in small amounts, unless it finds a really nice place to grow, like in your shoes or socks (That's what that smell is! Bacteria eating things...) A stream is not a great place for bacteria, and hence you don't have to worry about soaking your feet, even if you have blisters. There are a few notible exceptions (like when I got something called empotigo (or something spelled like that) when I was a kid from a damed (damned) pond. Every kid in the town had it and they had to drain the pond).
Not that I want to but.... I would step in poop..but I certainly wouldn't eat it...
I don't have all the answers, but I think it's easy to draw the wrong conclusions from anecdotal evidence.
As others have pointed out, LOTS of folks actually have, and spread, Giardia without knowing it. They just don't get sick. Other folks will get deathly ill.
I was once a farm boy, and for whatever reason, I am extremely resistant to stomach bugs. I can travel in third world countries and eat with wild abandon while other folks are collapsing along the way.
But I've apparently had Giardia twice (once confirmed.) It appears that both times I got it from tiny, ice-cold brooks. One was about a foot wide, one was a tiny trickle. One was in a remote part of Alaska, the other in an Idaho wilderness.
I would venture to say that the sickness rates of filter users vs. non-filter users is skewed by the fact that folks who get sick more easily are much more likely to use filters. So if I'm susceptible to Giardia, I can use a filter and if I make just one usage blunder, I may get sick while someone who has no symptoms will never appear to get sick.
I do agree with the theory that basic hygiene has a whole lot to do with it. Not allowing other hikers to plunge their filthy hands into your Gorp bag is probably more important than using a filter. Share your Gorp, but use the "pour method!"
Being a Wastewater Treatment Operator in Massachusetts, I use the same method used by most tap water facilities.
- Pre-Screen the Source (ie, Coffee Filter, I use the Siltstopper 2).
- Treat Chemically, I use Aquamira (Chlorine DiOxide).
Also use common sense. Don't try to treat putrid or septic water (duh). Think about what is upstream from you as well. If there is a cattle field 2 miles upstream, you might want to look for a different source...
I've spent the last 16 years analyzing surface waters for bacteria in my job as a microbiologist for the State of Vermont. A lot of the water samples looked and smelled just fine, but were loaded with bacteria. I've said this before, but it bears repeating: giardia is just the tip of the iceberg. Don't forget cryptosporidium, Norwalk virus, campylobacter, leptospirosis, E. coli 0157, rotavirus, and believe me, I could go on and on. I remember meeting a guy who was knocked off the trail by giardia, Giardia Don we called him. He eventually got back on the trail, but in a weakened state, and didn't complete his hike. Another guy told me he was immune to all bacteria. And he was serious! (The march of the clueless goes on). All I can say is, if your treatment system does not filter out viruses (and many don't), you're putting your trip at risk. And, if your treatment system doesn't kill protozoans like cryptosporidium (iodine doesn't), you're also putting your trip at risk. Sure, you might get away with drinking straight out of a stream, but why would you want to risk the most important trip of your life on a roll of the dice?
I filter all water,,,,thru my teeth !!!!! Been on trail constantly as hiker/maintainer for past 13 yrs. never been sick, but also have been mainly here in the south. I believe alot of symptoms suffered out there by hikers is hygiene related, gotta wash them hands and cooking utensils real good and alot, but I agree with Jack, common sense goes a long way in choosing what to drink. Hope this has helped you some.
Do you know what Aqua Mira (chlorine dioxide) takes care of?
The information that I have seen indicates that chlorine dioxide is effective against a wide spectrum of microbes, including bacteria, viruses, and protozoa. I've been using Exstream, haven't yet tried Aqua Mira, but would be interested in trying it.
Here's a good article on water disinfection.
Chlorine dioxide is supposed to kill crypto, which iodine doesn't. Note that the AquaMira bottle only claims to kill bacteria because it hasn't yet received EPA approval for water purification.
Communists were going to take over the world so we had 'duck and cover' drills in our schools, enough nuclear bombs to destroy the earth several times, Nike missile sites......
Giardia is going to destroy our lives, so we have profiteering in bottled water and water filters.
I'll stick to my $2.75 Sierra cup and common sense (which is usually free). I have never filtered water in my 28,000 miles of trail walking.(13 traverses of the ENTIRE Appalachian trail)
[QUOTE]Originally posted by warren doyle
[B]Communists were going to take over the world so we had the Berlin Wall.........,]
We didnt have the Berlin wall, they did. It was constructed By the East German side, to keep their people from the West.
But I will agree with your "common sense" approach...if your body has become accustomed to it.
How does common sense tell you if someone's Giradia infected dog has just taken a crap upstream of the otherwise pristine source you are drinking from? Or if the otherwise nice looking stream is really the run off from a beaver pond, hidden behind some trees? I treated very few sources out West, but I had no illusions that the water I was drinking was always pristine. I just hoped that if it had some baddies in it, my body could fight them off quickly.
i NEVER filter my water...i do use iodine tabs in "questionable" sources (non-moving water sources, etc)
and have gotten use to the iodine taste....
yes, i know about vitamin "C" trick to get rid of the taste....dont use it or need it. :p
I do not filter. Only my whiskey and beer are filtered.
My dad carried one of those nifty nylon water bags which made it easy to walk to the spring, collect about 1/2 gallon, carry it back to the shelter or campsite and filter as needed with the nearly-as-nifty MSR mini-works. At several shelters, during the rain, there was a nail or peg in the right spot to collect rain water running off the roof. Saved excess steps.
I don't use trekking poles so the filter pump helps me keep the biceps ripped.
[QUOTE=]Filtering, treating or not. It depends on where the source is. How you 'get' the source and what you drink from....+ lots o' other variables..... I use an MSR filter when the source is down, off the mountain, near a farm or industry, or housing, or humans, or near a road, or any where that could put anything in the water that could make me sick...'Cause it ain't no fun walkin' with the runs and smellin' up yoself. There are times when the source is piped or high on the Mt., or from a good lookin' cistern or covered source where I drink right out of the spring...Oh, 'Prescious Blood Of The Mother'....Don't think I could hike if I could't occasionally have a fresh drink. That's why its important to protect these sources up Da Trail and practice good etiquette around the shelters and priveys....and springs. There's always a chance some animal s**** the water, but that's a choice I'll make, based on knowledge and
experience....Good Water Sources to You All.....................[QUOTE...KZ@]
'It is neither wealth nor splendor, but tranquility and occupation which give happiness.'.......T. Jefferson
Interesting article on this general topic:
I have met thoes that don't, met thoes that do and met them that spent time at expensive hospitals. I am past fifty and just for saftey sake I filter.
HYOH Life is good.....Swamp Dawg
Do I use an iodine cartridge for viral bugs or not? Will I be fine just using my regular pur hiker without this attachment? These are questions I sometimes have. Most of the time I don't filter when in mountains at high elevations and near the source. Otherwise, I filter. I use a coffee filter for pre filtering and try not to use a fast moving water source, but, instead, a still body of water to pump from (less sediment).
Hygene is very important. Improper washing of hands, washing cookware, sharing bagged foods (chips, candy, popcorn etc.) with others, drinking and eating after others, things lots of people are guilty of and probably a cause of more trail sickness than bad drinking water.
I think that it is a question of the water source and location of that source. I consistently drink water from springheads without filtering or treating. Have never gotten sick from these sources. The water squirting out of the ground at a springhead has been squeezed through metric tons of soil, rock and sand. I drink well water without treating it, so what's the difference? According to a bio-engineer aquaintance of mine, most city water treatment facilities use sand filtration (metric tons of soil, rock and sand), but also add chlorine. He studies and monitors river water quality for the state of NC. He won't give me an opinion on not treating water from a springhead. I pump any surface water other than springs because you don't know what has entered the water system after it has left it's orgin. I will also pump or skip (if possible) water sources populated with freshwater snails. The snails are commonly infected with parasitic nematodes (a small microscopic worm) which can also utilize you and your body organs as a host. I carry a First Need Water Purifier, it weigh's 10 or so oz's, but I'm not an ultra lighter, the weight is insignificant to me.The only time I became ill was after a drank directly from a main stream in SNP.
I would rather not take a chance on getting the screaming heebie-jeebies. I always filter no matter where I'm at.
I filter all my water, even the water I wash with.
I heard someone recently got a 2 inch long leach up thir nose from not filtering there wash water.
1st of all, i don't filter water anymore. Did it in 96 on the PCT because i hiked with a girlfriend who was into filtering. But i drink most moving water, or if its a river, will try to wait until i find something smaller. Use common sense. With 20,000 miles of long distance hiking, i got sick for 24 hours once (in '95 in Connecticut when someone else got my water for me) but here's an alternative that i've been using since my brother told me about his Amazon experience:
When chaperoning for a south american class trip up the Amazon, my brother found out that they would fill a 50 gallon drum from the muddy river and add a capful (from a coca cola 2-litre bottle cap) of household bleach to the 50 gallons and let it sit for an hour. No one on the trip got sick! Ever since this story, i have been carrying a "Visine" bottle full of household bleach for those times when i find questionable water. (big rivers or places where i think someone may have cleaned their baby's diaper) I have been averaging only 3 or 5 times a thru-hike with treating the water this way. Even in Nepal last year, i was able to find running water coming out of the ground 80-90% of the time. I haven't been sick in 7 thru-hikes now. So, I believe if you are really worried about the water, save yourselves some weight and try this method: One drop of bleach per litre and wait 20 minutes (wait longer if the water is really cold) This is what cities and towns do to treat their water and it works. PUR would never want you to know this! fh
1st of all, i don't filter water anymore.
Have you checked your nose for leaches lately???
"...add a capful (from a coca cola 2-litre bottle cap) of household bleach to the 50 gallons..."
The problem with household bleach is that:
- it breaks down with time,
- Its concentration can vary from batch to batch and from brand to brand.
Also, I could be wrong about this but a capful of bleach does not sound like enough bleach for a 50 gallon container of muddy river water. I would advise upping the amount of bleach for that much water.
It's odd how the overwhelming majority of people voting in poll say they filter all the time, but the overwhelming majority of people posting responses seem to not filter at all
Good point JoeHiker. I noticed that a handful of those responding are oldtimers with well over 100,000 miles between them. It would be interesting to see what this poll would look like if it measured combined miles of each catagory. It seems to me that the more experienced and comfortable one becomes in the woods\mountains the less they filter. Common sense seems to be the main theme, but how common is that?! To most folks common sense is better safe than poopy. Nothing wrong with that, do what makes sense to you. As for myself, I often wonder- why are those folks are filtering that beautiful spring?
I think people who are filtering that beautiful spring realize that water that is clear and pretty from a distance isn't necessarily so pretty under a microscope. For example, Cryptospordia have been found in a large fraction of so-called pristine springs.
By the way, bleach, although it does kill many microorganisms, has been found to help crypto emerge from their cysts. It actually helps them complete their life cycle.
Think crypto is rare? Hardly. The word is ubiquitous.
Thanks Hog, now I know. I guess the more you know the more you have to worry about. I'm throwing away my bleach and packin my 'scope! Sorry to joke, I think you are right but I worry more about crossing the gap where hikers stroll in front of 55+mph, not always sober traffic. Now that scares me, probably because I saw 2 ALMOST get wacked yesterday. I know a couple of people who wont fly, one who wont ride a train, and a bunch who would never hike the trail. My couriosity and opinion are only based on personal experience however and it seems there are tens of thousands of people miles to make me feel better about my ignorance. And just because I play the lottery doesn't mean you should, the odds are off the charts don't cha know?!
I filter water from streams but not springs. I have been doing this for years with no ill effects.
Since I was in DC on Sept 11, 2001, I quit flying. (Never liked it anyhow, and 9/11 seemed like a good reason to "just say no".) Trains are 'way cool, maybe even decadent.
As a newbie -I've done SO much reading on both sides of this in trying to make my equipment selections.
I have decided to carry AquaMira and a filter. My thought is that as a newbie who has limited experience in finding water sources that I don't want to be stuck without water because the only source I found is iffy. That being said - as a day hiker I have often drunk directly out of clean streams/brooks to no ill effect.
As an FYI regarding using bleach - light weakens it. Which is why bleach is not sold in see-thru bottles. And it is also why you add chlorine to your swimming pool at night after the sun goes down and not durning the day. So if you carry it - carry a name-brand, in a light resistant bottle.
I think folks react differently to bacteria/viruses/spores -and I would say that folks that have fairly delicate intestinal tracks (ie my husband who catches every GI bug that comes down the road) should filter & treat all of their water.
Here's a question for you though.... for those that hike with their dog - do you filter/treat their water? Myra has been drinking out of clean streams/brooks for years with no problem on our day hikes (we don't let her drink out of standing or stagnant water). So I will probably only treat/filter the iffy water sources for her as well. And I have made sure she has great vaccinations (three extra hiking specific ones she gets in addition to her normal rabies/4&1 are Coronavirus, Lyme, and leptospirosis).
just my 2 pennies....
Are you kidding? I don't even drink my tap water, without filtering! Just know that all this water treatment is just saving you from getting sick immediately. You can't filter out all the pesticide/chemical runoff in the water, which is making you sick over time.
I filter or treat judiciously - occasionally take a chance on some springs in the mountains, but usually treat streams and ponds. Like Freiden said, getting sick doesn't actually prove anything about a particular water source, and NOT getting sick doesn't, either...hard to tell where an illness came from, and hard to know what to attribute our good or poor health to. Luck? Fortune? Filtering practices? The gods?
Nope, never filter and seldom treat. Haven't got sick once....