Carry less water
Backpacker begins its advice on how to carry less water with the disclaimer-esque "Don't risk dehydration, but be smart when water is plentiful. Use a map to plan refills."
That's all well and good, but what about water quality? Backpacker recommends that you "Skip the filter unless you expect murky water. Instead, opt for a chemical treatment or [...] SteriPEN Adventurer Opti ($100, 3.8oz)"
Backpacking North says...
Let's face it: water is heavy. Fortunately its weight is easy to calculate: 1 litre = 1 kilogram (or 2lbs per quart), although that's not much of a consolation when you've just got your pack weight down to single digit kilograms, only to load it up with 2kg of water. But do you need to carry all that water?
In this sense, Backpacker's first nugget of advice is perfectly sensible. If you are hiking in an area of plentiful water supply, then you really don't need to carry more than a litre. Have a good drink before you start, and hit the trail – if you know you're going to find water soon then why start off carrying it?
As for "use a map to plan refills"... well, duh! Unless you're hiking in the desert and plan on carrying your entire water supply with you, you should always do this. Make a note – mental, on your map, on your GPS – of places on your planned route where you are likely to be able to get a refill: springs, streams, lakes. Even if you are carrying all your water, it's wise to check the map for cattle troughs, stagnant ponds, or other potential emergency sources of water.
Which brings us to the meat of the matter: water quality.
Here in Lapland, much is made of the pristine waters into which you can theoretically dip your kuksa and drink to your heart's content, splashing water over your shirt and laughing hysterically at the sheer wonder of it all. But is that true, or is that marketing?
The situation was certainly very different in the Boundary Waters of Minnesota, where you'd be considered a little crazy not to filter or treat any water – and the same can be said for most of the United States. Considering that the landscape and wildlife of northern Minnesota are very similar to that of Scandinavia, can we really continue to trust that the waters of the Nordic region are as pure and untainted as we might want to believe? Recently, on my trips to refill at natural springs, I've seen signs (in multpile languages!) warning that "this water has not been tested". I'm almost certain I contracted giardiasis once while hiking in Lapland (although it was probably in Sweden, which explains a lot).
Hiking in desert areas is, of course, a different kettle of fish. While backpacking in Utah the need to carry all my water (including enough to cover any unforeseen emergencies) was back-breaking but critical. On several trips I drank every last drop, and could have used more – the problem being that in desert areas not only is there very little (if any) water available, but it is typically hot, so you need to hydrate more, and thus carry more water adding to the weight of your pack and your exhaustion/dehydration. It's quite the vicious circle. Carefully planned trips and awareness of potential (ideally confirmed) water sources are essential. And usually, precisely because those water sources are rare and therefore used by all manner of man and beast, proper filtration or water treatment is an absolute requisite.
The Sciencey Bit
So what are we talking about when we need to filter water? Well, first, at the visible level, there is particulate matter: silt, algae and detritus which give water an unappetising appearance but which can generally be filtered through anything from a buff to a coffee filter. In fact, with many filtration systems, it's better to pre-filter the water first to increase the effectiveness of the more hardcore filter or purifier in dealing with the larger (or, rather, smaller) problem: contaminants such as chemicals, micro-organisms and pathogens.
The most common contaminants you are likely to encounter are cysts and protozoa such as Giardia and Cryptosporidium, both of which will give you a nasty case of diarrhea. Fortunately, these are fairly large (on a microcosmic scale) at around 1 to 20 micron, and easily removed by most readily available filters.
Bacteria (such as E.coli, salmonella) are more smaller (between 0.1 and 10 micron), but less common unless you are stuck with really rancid water (or an animal has decided to die upstream). Filters typically remove contaminants down to 0.2 microns (better ones to 0.1 microns) and will keep you safe from both protozoa and bacteria.
Viruses (hepatitis,rotavirus, norovirus etc) are considerably smaller at 0.005 to 0.1 micron, and a different matter entirely. In order to remove viruses, you must move beyond simple filtration and purify the water, typically via chemical or UV treatment. In most developed nations, waterborne viral contamination is not an issue (although I read recently that, but if you plan to travel to developing countries (notably Africa) you'd be wise to take a purifier.
To summarize: Filters typically remove protozoa and bacteria down to at least 0.2 micron (and ideally down to 0.1 micron) and are sufficient most backpacking purposes. Purifiers remove or render inactive protozoa, bacteria, and viruses through chemical or UV treatment and are ideal for really awful conditions.
But in Finland the water is clean, the banks are secure, nuclear power is safe, and we have Nokia (oh... hang on...)
So what filtration/purification options are available?
There are several ways to treat your water, each having its pros and cons. Let's start with the cheapest:
If water is boiled for at least 1 minute (longer is safer) it kills protozoa, bacteria and viruses. The advantages are that it doesn't require any equipment you don't already have, and it only costs fuel. The disadvantages are that it takes time to boil, and time to cool, and doesn't do anything for the appearance or taste of the water. In fact, boiled water tends to taste a little "flat".
Pump filters are probably the most common form of filtration used by the average hiker. They're simple and fast, but only eradicate protozoa and bacteria. They also get clogged very easily and require frequent in-the-field cleaning, which can often lead to contamination issues if care is not taken. They are quite heavy and bulky, and water should not be allowed to freeze in them.
MSR SweetWater Filter ( 11 oz / 312g, >1 litre per minute)
MSR Hyperflow pump filter (7.8oz / 221g, 2.75 l per minute - uses similar tech to Sawyer)
Katadyn Hiker PRO (11oz / 312g, 1 litre per minute)
Gravity filters work in a similar way to pump filters, but let gravity do all the manual labour. Some work better than others. On the positive side, they are easy to use – just set them up and go about your business. Their speed varies between models, but their reputation for being slow is, in my opinion, increasingly outdated. Some models need in-the-field cleaning of the filter, others can be backflushed, Care should be takes not to let the filter freeze. Like pump filters they eradicate protozoa and bacteria. Some of the water bags tend to be over designed and on the heavy side. Gravity filters sold as sets tend to be heavier than the versions you can cobble together using in/line filters, and are often limited in their flexibility.
Platypus GravityWorks filter (10.6oz / 305 g, 1.75 litres per minute)
Sawyer 2 & 4-Liter Gravity Filter Systems (16 oz / 453 g, 1.7 litres per minute)
Sip/squeeze bottles / in-line filters
Much like in-line filters in platy mode, a sip filter screws onto the top of a bottle. You fill the bottle with dirty water and suck out clean water through the filter. Some newer models allow you to squeeze water through the filter, creating a kind of manually-assisted gravity filter. They are gaining popularity because of their light weight and idiot-proof use. They filter protozoa and bacteria, and there are many of them in the marketplace.
Sitting somewhere between gravity filters and bottle filters are "do-it-all" in-line filets. These can be fitted between a dirty water source and a clean output. They are designed to be adaptable to many uses: gravity feed, in-pack platypus filter (just fill a platy with dirty water and suck clean water through the filter), or in a bottle. They filter all of the same bad guys as other filters, and can do so at a fair clip (the Sawyer below filters 1.7 litres per minute). They do require post-trip backflushing, and might take some imagination in setting up a flexible system (but at least you can create a ultralight one). They are however light and relatively trouble-free. Incidentally, Sawyer guarantee their filters for 1 million gallons! Pinch of salt, anyone?
Sawyer PointOne Squeeze filter (3.5oz / 99g dry, flow rates depends on your squeezing skills)
Sawyer All-in-One Squeeze / Gravity filter (similar to PointOne Squeeze, but includes gravity kit etc.)
Sawyer 3-Way In-Line filter (1.7 l per minute / 2 oz (56g) dry)
Sawyer 4-Way In-Line Filter System (similar to the 3-Way, but includes bottle)
DrinkSafe Aquaguard Eliminator (A UK filter much like the Sawyer. 300ml+ per minute, 71g / 2.5oz. )
Travel Tap (150g / 5.2oz)
Super Delios (40g / 1.4oz excluding bottle)
Aquapure Traveller (145g / 5oz)
DrinkSafe Waterstraw (40g / 1.4oz)
Frontier Pro filter (2oz / 56g) (Note: Frontier pro filters are rated only to 3.0 microns, but Aquamira claim their technology still provides adequate filtration. They are also limited to filtering 50 gallons. See discussion at Backpacking Light.
Frontier Pro Bottle Adaptor (weight unknown)
Ultra-violet light disrupts the DNA of microorganisms, rendering protozoa, bacteria and viruses inactive after exposure for a short period of time (around 90 seconds). UV purifiers are light weight, simple to use, and very efficient. The downsides are that murky water should be pre-filtered as it impedes the transmission of light, and as the devices are electronic (powered by batteries) they can, on occasion, fail. Reliability has improved (I'm told), but a backup should always be carried.
SteriPEN Adventurer 3.6oz / 102g (inc. batteries)
New: SteriPen Freedom 2.6oz / 73g (exc. charger - looks good, but I'm hesitant about rechargeable batteries in the wilderness – better to be able to carry spares. Also, initial reports seem to indicate sporadic failures).
The ultimate ultralight solution, chemical treatment of water via iodine, chlorine dioxide or (if you dare to go there) bleach. Iodine is ineffective against cryptosporidium, and less effective anyway at cold temperatures. It's use has also been banned in the EU. Bleach likewise is not good for cryptosporidium, and both iodine and bleach will taint the flavour of water. Of the three, chlorine dioxide is the better choice. It kills all bacteria, protozoa and viruses, but absolute effectiveness against cryptosporidium can take some considerable time (up to 4 hours, although many users wait 30 minutes and start praying while they're waiting). As far as taste is concerned, chlorine dioxide is said to improve the taste of murky water. For it's weight and price (at least in the short run) this is by far the best option for the ultralight hiker.
Aquamira Chlorine Dioxide Water Treatment Drops (popular, long lasting, good value for money, but take 4 hours to reliably clear cryptosporidium)
Aquamira Water Purifier Tablets (also popular and convenient, better for winter)
Katadyn MicroPur Tablets (alternative to Aquamira)
What does Backpacking North use?
When I arrived in America I was surprised and befuddled at the peculiar obsession with filtering water. I paid a visit to Midwest Mountaineering to figure out which filter would be best, and ended up getting an MSR Sweetwater pump filter.
At first I was oddly excited by the idea of pumping away and producing spurts of pure water joy from the murky brown lakes in the BWCAW. That was on day one. On day two, pumping already started to get a little difficult. But day three, the pump was incredibly hard to use, and every attempt resulted in the pump's pressure release valve squirting dirty water all over me – and in the BWCAW (a.k.a. Beaver Kingdom) youreally want to avoid contaminated water.
Cleaning the filter wasn't difficult, although the little brush had a tendency to flick lake gunk all over my face. Unfortunately, although it was easy to clean, cleaning had little effect on productivity. It made pumping a little easier for while, but by the next day it was pretty much useless again. Needless to say I was quite annoyed I'd wasted $85 on it.
I began my search for an alternative. I'd read about the Frontier Pro, and seen a couple of videos on YouTube that made it look quite promising. It was certainly lighter at 2oz. It was really cheap ($25). It could be screwed onto a bottle, or used as a gravity filter. The only downside was that limit of 50 gallons. So I ordered two. Cunning, huh?
While they were on their way to me, I happened to notice the Sawyer in-line filter in a local store, with "1 MILLION GALLONS GUARANTEED" shouting at me in big, happy letters. It weighed the same as the Frontier Pro, and as far as I could tell, the design would allow me to create a better gravity system than the Frontier Pro (the Frontier attaches directly to a platy, but with the Sawyer you can separate the filter from the platy, thus increasing pressure and flow rate). I decided to get the Sawyer and sell the Frontier Pros.
It took me a little while to create an ideal set up. At that time the Sawyer filter was a little simpler in design – now it comes with some simple tubing attachment clips so you can more easily swap it from gravity filter, to in-line platy/reservoir filter, to squeeze filter.
I was pretty amazed at the speed of filtration – it's very fast. You can set up a 2 liter platy in camp and after a couple of minutes it's all done. The taste is clean, it's easy to backflush in the field – although I never needed to – there's no mess. Put simply, it just works. I've been very happy with it and can recommend it wholeheartedly.
Now I'm back in Lapland, do I still need to use it? According to folk wisdom, apparently not. Maybe I'm foolish, but I tend to think it would be overkill. Although the filter itself weighs only 56g, once you add in all the piping and platys it rises to >250g.
I've been thinking about getting a SteriPEN and using that. At 100g including batteries, it weighs less, and takes up very little room. The question is, would I really use it? There's not really any point taking it unless you use it all the time, and I'm fairly certain I can find ample clean water in Lapland, or at least water that is extremely low risk.
The other issue with the SteriPENs is that every single person I have hiked with who has used one has experienced a failure of one kind or another (and ended up using my Sawyer). I've heard the new Adventure models are more reliable, but I tend to think that if an electronic device is going to fail, it's going to fail on the trail, so you always have to carry a backup anyway. If I need to purify, I can just boil any suspicious water, so I suspect the only reason I might be interested in a SteriPEN is gear fetishism.
I would use Aquamira drops or tablets, but I've not seen any for sale locally – probably because of the aforementioned "purity" of the waters. In fact, now I think of it, I haven't seen any filters of any kind for sale in Rovaniemi.
So, I think for the moment it's the Sawyer for travel in places I'm not confident have good water, and faith in the purity of Lapland waters while on my home turf. I might one day switch to the Squeeze, but for now my in-line filter is simple, light, and reliable. And that's all I need.
One other thing: what about carrying water?
Good question! I've been a convert to collapsible plastic bottles for the last few years – mine are 1liter ones from Platypus. I generally keep at least one in a side pocket of my pack. If I'm carrying the Sawyer, and depending on the water resupply situation, I might fill a designated dirty reservoir, slip it in my pack and fit the filter/mouthpiece to it so I can drink handsfree while on the move. It the water tastes a bit gunky, I'll add a Nuun tab straight in the dirty water bag – the Sawyer can handle it – and get some flavoursome electrolytes while I'm at it.
Joe and Dave have a few very valid things to say in favour of hard plastic Nalgene bottles, not least of flexibility as multi-use items (e.g. sock dryers, hot water bottles, cowboy coffee makers). The wide mouthed nalgenes are also much easier to fill than narrow mouthed, flexible bottles. Try to make sure you get a BPA-free one though.
What do others use?
Ryan Jordan seems fond of his SteriPEN, while Andrew Skurka states a preference Aquamira drops on his long treks in his excellent Ultimate Hiker's Gear Guide.
The Jolly Green Giant has been using a Lifestraw, Katadyn Micropur tabs, and the interesting Super Delios. I like the look of the Super Delios, so I'd be interested to hear comments from anyone else who has tried one.
A quick survey of mostly UK-based twitter peeps (@munro277 @HelenJFisher @PhilOutdoors@nigep @JourneymanTrav – follow them all!) reveals the Travel Tap to be most popular, with the Sawyer Squeeze a close second, followed by the Drinksafe Water Straw. @atirila uses a Frontier Pro with Micropur tabs, and he's in Finland. Another sceptic of Nordic purity?
Talking of the Sawyer Squeeze, Philip reviews it favourably at Section Hiker, and Stick offers a comprehensive review (with additional video links). HikeLighter also has very thorough coverage, as doesWood Trekker. All seem to give it a good thumbs up. If I were to pick one problem with it it would be the size of the pouch mouths – they are of the small variety, making it harder/slower to fill them from lakes and streams.
If you just can't stand wading through another link to our corporate overlords, Brian's Backpacking Blog has you covered: follow his instructions on how to make your own filter.
Sawyer Water Filters
Drinksafe Filters (Travel Tap, Waterstraw, Aquaguard)
Aquamira (Froniter Pro and Aquamira drops/tabs)
Cascade Designs / Platypus / MSR
REI article on Water Treatment
Another REI article on water treatment
Mike Clelland! on drinking untreated water
Jolly Green Giant on water treatment options
Ryan Jordan on backcountry water treatment
Backpacking Light Water Treatment reviews
Backpacking Light Water Treatment Series