May 10 2017

The Sawyer Mini Water Filtration System: Small Is Beautiful by Tamia Nelson

Quenching your thirst is surprisingly difficult, whether you’re cycling through rural country or trekking in the backcountry. You just can’t assume that wild water is safe to drink. Which explains why clever people have devised many ways to disinfect questionable water. Tamia has weighed her options for how to treat wild water, and the winner is… the Sawyer Mini.


Whether I’m heading out on a long bike ride along back roads with no services, paddling a lonely stream, or bushwhacking into a favorite beauty spot, I have one nagging worry: drinking water.

The Adirondacks, my backyard, is a well-watered place, but trekking is thirsty work, and there’s really no way for me to know if wild water is drinkable. The only valid rule of thumb was articulated many years ago by veteran desert walker Colin Fletcher: “If in doubt, doubt.”

Back in the day, it wasn’t uncommon to find a dented tin cup upturned on a stick alongside a stream or spring hole. And I drank my fill at such informal watering spots many times without any qualms. But times change. Nowadays there’s likely to be a 100-unit second-home development just a mile upstream. Or maybe the last person to pass by thought the spring hole was the perfect place to take a bubble bath. Or the trail might be popular with local dog-walkers, all of whom think pooper-scoopers are for city folk.

Which is probably why you don’t see many tin cups by streams these days — and why I’m left with only Fletcher’s Law to guide me: If in doubt, doubt. And then? Treat the water! It’s not as if there aren’t a lot of options. But before deciding on the best method for my trips, I thought I’d better get a clearer idea…

WHAT WE’RE UP AGAINST

The answer? Just about anything I cared to name. Pathogenic bacteria. Protozoan parasites like Giardia and Cryptosporidium. The eggs of infectious tapeworms (Echinococcus). Even waterborne viruses. Not to mention chemical contamination — that devil’s cocktail of subtle, insidious poisons that we regard as the inevitable price to be paid for progress and prosperity.

That said, I’m not likely to find all of these in one cup of water. But who wants to play Russian roulette with her health? If in doubt, doubt, and take reasonable precautions against foreseeable risks. The bad news? The risk posed by the chemical contamination of surface waters and aquifers can’t really be assessed or addressed in the field. While the activated carbon filters found in some portable filters may indeed improve the taste of water,…

ACTIVATED CARBON FILTERS DON’T REDUCE THE BURDEN OF TOXIC ORGANIC CHEMICALS

Is this a concern? Yes and no. Though there’s not much heavy industry in the Adirondacks, there are mines, commercial forests, farms, and lawns, all of which are fertile sources of noxious pollutants. (Yes, even lawns. Could any McMansion owner forgo having a vast sweep of lawn, maintained with an arsenal of pesticides, herbicides, and fertilizers? Certainly not. What would the neighbors think?) There’s also direct contamination of surface waters by runoff from parking lots and highways, not to mention the oil-rich exhausts of the outboards, jet-skis, ATVs, and snowmobiles beloved of many outdoorsmen and outdoorswomen.

The bottom line? The water flowing brightly under the road bridge, gurgling down the trailside stream, or passing under my keel may well be chemically polluted. And there’s nothing I can do about it, except hope that the risk is small. Or drink only bottled water — not really a practical alternative on long trips away from “sivilization.” Having said that,…

SOMETHING CAN BE DONE ABOUT PATHOGENS AND PARASITES

In fact, when it comes to disinfecting water, I have an embarrassment of options. I can boil it. I can dose it with a germicide. I can filter it. I can even zap it with ultraviolet light. That’s almost too much choice, which is why I decided to narrow the field before coming to a decision, weighing the merits and demerits of each method in turn, beginning with …

Boiling.  What could be simpler? Fire up the stove. Bring a pot of water to a good, rolling boil. Then — since I won’t be camping above 14,000 feet — I’m done. But nothing’s really this simple, is it? Boiling water has to cool before you can drink or decant it, and I’d need a big pot (and plenty of fuel) if I were going to boil up enough to see me through a sweaty day. In other words, boiling makes sense if I’m just brewing a pot of tea or making coffee for breakfast, but it’s an awkward and time-consuming way to meet all my drinking water needs.

OK. Boiling’s out, at least for disinfecting water in bulk. But I can always fall back on science, can’t I? What about …

The Pharmaceutical Option?  There’s nothing easier than popping a pill or two in a bottle of water, is there? No, but many devils lurk in the details, nonetheless. To begin with, two old campaigners are off the list. Halazone [4-(dichlorosulfamoyl)benzoic acid], the chlorine-releasing tablets handed out to GIs during World War II and still in widespread use as late as the 1960s, start losing their oomph almost as soon as you open the bottle. And tetraglycine hydroperiodide (the original Potable Aqua), though made of sturdier stuff, with much greater staying power than Halazone, is off-limits for anyone with thyroid disease, a cohort that now includes both me and Farwell. That leaves chlorine dioxide. The upside? Treated water still tastes like water, rather than disinfectant. The downside? Treatment time is four hours. And the tablets aren’t cheap. Moreover, it’s by no means certain that any chemical germicide is effective against the embryonated eggs of hydatid tapeworms, an emerging concern as Adirondack waterways become busier (and doggier) places.

My verdict? The pharmaceutical option was also out. But I thought I might have found my answer in another fruit from the tree of technology:

The Lightsaber.  This is Farwell’s whimsical name for the SteriPEN, a portable ultraviolet (UV) generator that bears a striking resemblance to an electric carving knife. UV radiation doesn’t kill microbial pathogens outright, but it does damage their DNA, limiting their ability to reproduce and thereby preventing them from overwhelming a human host’s defenses. The SteriPEN is an ingenious device, light in weight and easy to use. That said, it isn’t without drawbacks. It’s fragile, for one thing. For another, its efficacy is somewhat impaired in turbid water, and not all Adirondack waterways are crystal clear. But here’s the clincher: I’ve found no evidence that it inactivates the embryonated eggs of the hydatid tapeworm, surely one of the nastier surprises lurking in wild waters. Bad luck, that. Looks like it’s Worms 2, H. saps 0.

And that’s three down, with only one to go:

Filtration.  Portable filters have been around for a long time, and they do a good job holding back pathogenic bacteria, protozoan cysts, and tapeworm eggs. But many that I’ve seen (and used) have struck me as impossibly fussy and rather accident-prone. One of the best, the venerable Katadyn Pocket, is not only breathtakingly pricey, but it also boasts a ceramic filter. The filter is easy to clean, and it lasts a long time in ordinary use, but if you drop it on a rock, you’re back to boiling water. Moreover, like many other portable filters, the Pocket allows pathogenic viruses to slip right through. That said, an MSR AutoFlow Gravity Filter has been our go-to solution for bulk water purification for some years now, though we also zap the filtered water with the Lightsaber to hobble any viruses. As the AutoFlow’s name suggests, it has no pump, and that’s a very good thing, indeed. Pumping is always a bit of a nuisance, and the absence of moving parts in drip filters like the AutoFlow eliminates many failure points. Still, the MSR is rather bulky, and packing it up is a little like wrestling an octopus. Ours is also getting a little long in tooth.

Which is why I started looking around for a smaller (and hopefully cheaper) alternative. And I found it on the shelves of the local HyperMart:

THE SAWYER MINI

Sawyer calls it a “water filtration system,” and I won’t argue, but it’s really just a small filter cartridge paired with a sturdy laminated “squeeze pouch” and a short length of rubbery tubing, plus a plastic syringe thrown in to make backwashing easier. And at around 20 (US) bucks a pop, it’s pretty cheap.

Sawyer Mini Filtration System (c) Tamia Nelson

Photo A above shows the Sawyer Mini in its retail garb. Stripped of its packaging, the entire “system” — filter cartridge (B), rubber tubing, rolled squeeze pouch, and a 60-mL syringe (C) — weighs less than four ounces. Simple it may be, but the Mini is nothing if not versatile. You can …

  1. Use the squeeze pouch to force water through the filter into any handy container (Photo D below).
  2. Attach the tubing to the intake end of the filter — do NOT confuse the intake and outflow nipples! — then immerse the end of the tube in a water source and suck away at the outflow till your thirst is quenched (E).
  3. Screw the filter directly onto a plastic seltzer or soda bottle filled with “wild” water and drink from the outflow nipple.
  4. Mount the filter in the line leading from a hydration bladder.

Sawyer Mini Filtration System (c) Tamia Nelson

I mostly stick to Option Number One. And how does the Sawyer Mini work? I’ve no complaints to date. It’s easy to pack and simple to use. But does it do the job? Good question. Sawyer has lab data supporting the filter’s efficacy against bacteria and protozoan cysts, and the filter itself seems reasonably sturdy.

So far, so good, but…

ARE THERE ANY DOWNSIDES?

There are. If a Mini is exposed to freezing temperatures after its first use, it’s toast. That drawback isn’t unique to the Mini, by the way. All hollow fiber membrane microfilters share this vulnerability. And since you can’t inspect the filter element without sawing through the housing, you’ll have to take its integrity on trust. Or not. Which is why I’d be inclined to season Sawyer’s claim that the filter is good for “up to 100,000 gallons” with a fistful of salt. In fact, one preliminary study reports that samples of a nearly identical Sawyer filter succumbed to irreversible fouling (and possible burst fibers) after two years’ household use, with consequent loss of efficacy. That’s why I intend to replace my Mini every year, without fail. Better safe than you-know-what.

THE BOTTOM LINE?

The Mini ticks all the boxes: It’s small. It’s light. It’s simple. Keep it warm when the thermometer dips to freezing and below, and carry a box of chlorine dioxide tablets to serve as an emergency backup in a hard chance. The Sawyer Mini’s not perfect, but it will do the job I need done. It might be just what you’re looking for, too.

Sawyer Mini Filtration System (c) Tamia Nelson

Product Evaluations Policy  TN Outside never accepts payment for product endorsements, nor do we accept product samples from manufacturers or their representatives. We write about the food we buy on our weekly rounds, and about the gear and books we’ve purchased, rented, or borrowed (from friends, family, or the public library) over the years. That said, on rare occasions we’ll write a product analysis of something we don’t own and have never used, based solely on the manufacturer’s claims, published specifications, or others’ experiences. But when we do that, we’ll tell you.

This article is an updated and modified version of one that appeared originally at Paddling.net on 12 May 2015.

Questions? Comments? Just click here!