I always carry a Steri-pen, and think it's pretty awesome. The weight is pretty trivial, it's easy to use and leaves the water tasting better than chemical sanitizers.

I know plenty of people happy with the Sawyer Squeeze filter as well.

Both weigh only a few ounces and provide a margin of safety that wild water doesn't. Cost aside, unless you know you're going to be doing very urban touring, I see very little reason not to carry one.

I don't carry one because I stay in state parks that have drinking water. I do own a water purifier and not a water filter, a purifier takes out harmful bugs and such, but I have yet to take it on a bike trip, though when, or if, I do my across America touring ride then I'll take it but I'll probably get a smaller one since mine is about 20 years old and since then smaller ones have come out.

I think you are confused about the difference between a water purifier and a water filter. Water filters, like the Sawyer, Sweetwater or Katadyn, have small enough pores to remove harmful bugs down to a certain size. The pores usually aren't small enough to remove viruses but they do a very good job on most water borne pathogens. Some of them, like the Sweetwater, may have a carbon layer layer to absorb chemicals that may be in the water.

A water purifier is usually just a carbon absorbent that may or may not have pore sizes small enough to filter out organisms but it's main function is to absorb chemicals. The problem with carbon absorbents is that you have little idea of how much capacity the absorbent has left and the absorbent is usually only good on organic chemicals. Heavy metals probably aren't going to be absorbed that effectively. Dissolved salts aren't going to be absorbed at all. Dissolved salts, especially if they are alkaline in nature, can give the water a very bad taste. I would highly suggest that if you are doing the TransAm, that you not drink any municipal water from Pueblo to at least the Kansas border along the route. Every town down there has just horrible water and no purifier can make it taste better.

Actually you're slightly confused but not far off; see: Backpacking Water Filters vs. Water Purifiers Mine combines a filter system with a purifying system to kill bacteria, but technically according to the instructions they labled it a Microbiological purifier because it goes beyond what a filter does. Mine is a pump style that looks like a short fat bicycle pump called a Pur Scout with a ball on the water side that has a small pleated paper filter inside which I add to it by rubber banding a coffee filter around the ball, inside the main tube there is another finer filter, then inside of it there is a carbon block, then above that is a iodine resin that looks like a disk about 1/4 of inch thick, then after that another carbon block disk (going from distant memory, I would have to find the unit and take it apart to see if I'm explaining this correctly). This system worked fine when I was doing some things overseas with very questionable water but the filter is old now so I wouldn't trust it anymore and I can't get Iodine or the carbon end pieces that stacked on top of the filter which is still available. When I was overseas I added 3 or 4 drops of bleach per liter and wait at least 30 minutes for the bleach to work just to be safe, boiling was out of the question where I was at most of the time. This system from Pur that I have I got because back then WHO recommended it for use in 3rd world countries, and it was the only one at the time that would remove even chemicals, which supposedly even today there are very few if any small size back packing units that will remove chemicals like heavy metals and other industrial chemicals. The cool thing about the filter inside is that it could be washed out and reused.

Todays modern stuff you can get a UV pen to kill all bacteria and viruses, but you are then dependent upon a battery. UV has been around for a very long time but only in the past 20 years or so got it down to a pen size device.

I'm not confused at all. As a chemist...unlike biologists...I know the difference between something that is "pure" and something that is sterile. Adding chemical treatments to water doesn't make it "pure" but it does kill organisms. For water to be chemically "pure", then it can only be "water". No dissolved salts, no dead organisms floating around in it, and no chemicals left over from killing the organisms. "Pure" water, in the chemical sense, is known in the trade as 18 MΩ (megaohm) water. That's the electrical resistance of "pure" water which won't conduct electricity. If you put iodine or sodium hypochlorite (aka "bleach") in water to kill organisms, it is far from chemically pure.

Filters remove large particles (sand, dirt and beaver poop:eek:) as well as most organisms. They don't work to remove any dissolved solids...salts...but then most consumer water "purifiers" also don't removed dissolved solids. Most consumer purifiers remove organic molecules from the water by absorbing them on to a carbon matrix but the carbon matrix doesn't work well on ionic substances like dissolved salts.

You also can't just "wash out" a carbon filter and reuse it...at least not wash it out with water. Carbon hangs onto organic chemicals pretty strongly and you might be able to get them away from the carbon if you had the right eluent but that's going to be specific for each species of organic compound you have on the carbon and would require lots of eluent (solvent flowed through the carbon). It wouldn't be worth the time and effort to do the wash.

I doubt, highly, if the PUR removed heavy metals. It may have been effective on the organics but the carbon filters would have become ineffective very rapidly due to their small size. If you want to get to MΩ water, you have to use several steps that exchange the ions in the water with other ions and then remove even those ions. It's not something that you can do out in the field. Distillation would do the trick as well but even that is difficult and energy intensive.

The problem with the article you linked to is that they don't discuss what a "purifier" is at all.

UV has other problems as well. It doesn't work on turbid water (water with rocks, dirt and beaver poop:eek:) in it. The UV has to get all the way through the water or bad little beasties can hide in the rocks, dirt and beaver poop:eek: You'd need a filter to remove all that stuff and, since the filter is as effective as the UV and you don't need to huck around batteries for it, the filter is a better way to go.

Cyccomute, I can't argue with "pure" vs. "contaminated", but rekmeyata is correct regarding terminology in use by the EPA for personal water filters and purifiers.

"So, what really is the difference between a backpacking water filter and a backpacking water purifier and why might you opt for buying one over another? To put it in the simplest terms, a water filter gets rid of protozoa and parasites, even bacteria, but it does not remove viruses. A water purifier eliminates all of these plus viruses. In fact, the Environmental Protection Agency has set standards that require water purifiers to eliminate 99.9% of all viruses. "
- http://www.backpacking-guide.com/water-filters-vs-purifiers.html

According to the EPA, almost all filters are not purifiers (the one exception I know of is a version of the Sawyer, which is a real pain to use unless you really need it, as the pore size is so very, very small). The Steripen (UV) is a purifier by the same EPA standards. If you want more on this, you might log onto backpackinglight.com which has many and detailed threads on various filters, purifiers, etc.

When encountering turbid water, I've had no problems doing a rough filter through a bandanna, then treating with the Steripen, then zapping it a second time, per Steripen directions. I do travel to some very remote international destinations, and have had no problems using this technique. The weight of Steripen plus two spare batteries is 4.76 oz/135 g by my digital scale. Pretty darn light. I have never had any failures in the field, and carry the extra batteries simply as a precaution, like I carry a couple of firestraws, in case I get caught in a bad downpour and need to start a fire in wet conditions. My backpack weight for a 1 week trip is under 25 lbs. including tent, sleeping bag, food, two liters of water, and a bear cannister, even with those two extra batteries and firestraws.

The Sawyer Mini, with either the Sawyer bar or an Evernew .9 l bag is 3.84 oz/110 g. That includes the backflush syringe.

You seem not to want to do any maintenance on your filter. (Please correct me if I'm wrong). Yet I'd bet good money that you regularly lube your chain, especially if you're about to do a century or some other long ride. Why should another mechanical device, a filter, be any different in needing regular and specific maintenance?

FWIW, I don't carry the syringe. I find that I can backflush whenever there is running water, by holding the filter against a faucet. Also in a pinch a bottled water or soft drink bottle can substitute for the syringe. I make it a point to clean the filter once in a while and before it needs it when on tour. I used the Sawyer Squeeze a good bit and then the Mini a good bit as well and do not recall ever using the syringe.

Exactly, and when I had to do some things in 3rd world countries WHO provided me with the information as to which backpacking system would work the best, and the Pur Scout was the only one at that time that meant all those needs including heavy chemicals, which supposedly where I was going there was that and more. Now did the system work as WHO claimed it would? I don't know, but I do know this...I never got sick and I'm still alive today, so in my book it worked great. As far as drinking dead bugs...so what? their dead. By the way, the Pur Scout was also issued to certain members of the military who were involved in certain 3rd world places.

I generally have not been too concerned about viruses where I have camped and used a filter. But if I was concerned about viruses, I would filter the water and then add some chlorine bleach. I noted above that I use 4 drops per liter of bleach when I use it, that is roughly twice the EPA recommendation for emergency water supplies.

When I backpacked on Isle Royale a few years ago, they were very clear that you should either filter or boil. Other treatment methods were insufficient against some parasites common to the area due to the moose population. Bottom line - different areas have different water situations.

Sorry but the EPA is using the term "purifier" incorrectly...many biologists do. They are describing a sterilizer. "Pure" means something else entirely.

The Sweetwater, by the way, meets the EPA's (wrong) definition of "pure" with the addition of a chemical treatment. That still doesn't mean that the water is "pure" in the chemical sense, which is the correct way to use the term.

Quote:

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Comprehensive Protection: Inactivates 99.99% of waterborne viruses, eliminates over 99.9999% of all waterborne bacteria and 99.9% of common protozoan parasites, such as giardia and cryptosporidia, as well as particulates.

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I too find that filtering is adequate but I'm careful about sourcing the water especially here in Colorado where mine drainage can be a problem.

One further item is that most people don't boil water correctly to sterilize it. At sea level, the EPA says 1 minute at boiling...actual boiling not just hot...although I've seen some studies that say 1 minute isn't enough. When you get to my altitude, 1 minute doesn't cut it because the temperature of boiling water is 203F not 212F. EPA say 3 minutes for up here which probably isn't enough. If you go to tree line...11500 feet...the temperature of boiling water is reduced to around 190F which requires 30 minutes of actual boiling. That's a lot of fuel.