Living here in Australia, a country that is ironically surrounded by water, with a bloody great desert in the middle and frequently parched by drought, I now take it for granted that I need to carry a good amount of drinking water on hikes (bushwalks) and need to know how to treat drinking water that I gather along the way.
I got a surprise when I received a comment from a New Zealand reader, when I mentioned that I sometimes take 3+ litres on bushwalks in Summer. This is only when I can’t confirm that there’s going to be any water to gather along the track and the temps look like being above 27C, but even that isn’t a hard and fast rule.
Although there are nasties in some rivers and streams, like cryptosporidium or giardia, I try not to feel too smug (OK, maybe just a bit!) when speaking with overseas outdoorsy types and tell them that we can still drink straight out of some creeks and rivers, without treating the water first. This is one of the reasons that I love walking in the more remote parts of the Blue Mountains and Kanangra-Boyd National Parks (and many other spots in Australia). It’s just one of the many rewards of the physical efforts required to get to such places… woo hoo!
Sydney’s main water supply, Lake Burragorang, Blue Mountains National Park.
How do you know if water is safe to drink?
As much as it would be helpful to have a little red or green light, magically suspended above a water source to let you know if it was likely to have you driving the porcelain bus for a week or not, Google haven’t figured that one out… yet.
Essentially, I don’t think there’s any way of knowing 100% if water is going to make you sick or not. Whenever I drink from natural water sources, I take a calculated risk and run through some questions in my mind:
1. What’s Upstream?
This is where being able to read a topographic map can be really helpful. Even if you’re miles from any town or human settlement, look at the catchment area for the water. What’s draining into it? Is it grazing land with cattle? Farmland with potential for pesticides and other agricultural chemicals? What about mining?
Being able to interpret a topographic map can help you learn about water quality.
2. What’s the history of the catchment and area?
So, there might not be farming there now, but maybe there was recently or there could be an old mine with ground water and mine tailings now washing through into the creeks (eg. Grose River, Blue Mountains NP) or even an old sewerage treatment works like Hat Hill Creek at Blackheath… yummy!
3. What’s the current usage and traffic of the catchment?
Although a spot might be National Park, it may have a popular camping spot where not everyone (you know who you are… Grrrr!) practices good toileting and hygiene habits, or may have brumbies or wild pigs in the area.
It looks crystal clear… but how do you know what it will do to your guts? (Ettrema Wilderness)
4. What does it look like?
Now, I’m no ecologist or scientist so my knowledge of the creatures that live within water is extremely limited… OK, it’s non-existent, but I do know that if you have a good working knowledge of such things, there are some little critters that can indicate the relative safety of the water. For myself, I stay away from those indicators… it’s safer, and one thing I never do is judge the safety of a water source by how it looks.
In my early days of hiking, (before I could read a toppo and learnt that we were only 1km from a great drinkable flowing creek out of a natural spring) I was forced to drink from a hideous black, non-flowing, mosquito ridden, damn, with a tasty layer of diesel fuel on top. Let’s just say, that like Huon Hooke, I would say that it left an interesting after taste (!), but strangely, it didn’t make us sick.
Contrasted with the time I ended up with a particularly explosive dose of liquid diarrhoea (TMI) from drinking a crystal clear, free flowing creek 100m upstream from a popular campsite in a National Park.
Lesson learnt.
Could this be the perfect campsite? With boiling the water on the fire, the water becomes drinkable… and perfect! (Coxs River, Blue Mountains National Park).
How to Treat Drinking Water
There are several different ways for treating drinking water that are popular with bushwalkers and hikers.
Personally, because I like to practice lightweight hiking, the two easiest methods that work for me are:
1) Tablets
- lightest option
- easy
- read instructions but generally have to wait 30mins before drinking
- have expiry dates
- available from chemists/drug-stores or outdoor retailers
2) Boiling
- Must hold at a rolling boil for minimum of 1 minute.
- Duration of boil increases with altitude.
- Tip: boil water at night for next day’s supply, so you need to have enough containers to do so.
Other popular methods are:
3) UV Light Sterilisation – eg: Steripen (battery operated)
4) Drops
5) Filters
Try to gather water from where it is flowing freely. (Kanangra Creek, Kanangra-Boyd NP)
If you’re really interested in going into water treatment methods more, you’ll find a whole lot of websites dedicated to the stuff if you do a bit of Googlin’. Including people arguing at lengths about the pros and cons of each method.
For me, I just want something fast, easy and lightweight. I don’t care too much about taste… so suck it up princess.
Now, for obvious reasons I’m not going to tell you not to treat drinking water. We’re all grown-ups (mostly) and need to take responsibility for our own actions – wise or otherwise – and if I’m ever in doubt, I will always just pop in a Puritabs/Aquatabs or similar. They’re lightweight, tiny and a cheap insurance policy against some serious squattin’ time!
Whilst on 6ft track 2 years ago, I met a PhD student from Imperial College who had just got approval to use a supercomputer to prove that UV light pens were useless for sterilising water. He boiled everything for ten minutes. Not even risking rain tank water. They got very thirsty after running out of gas for boiling half way along the track.
Of course, if water is contaminated by mine water, neither boiling nor steritabs will remove metal ion contamination.
And if water is peaty black but healthy, chlorinating it will ironically turn those safe organic compounds into carcinogenic ones.
Personally, I chose to risk even the most dubious water supply sources as an expat hydrogelogist whilst looking for groundwater alternatives for 40 towns and villages in Iran and only experienced a tummy upset for one afternoon over that 2 year period.
And in Burma I ignored good advice to only drink water taken up country from leading hotels, etc and remained perfectly healthy whilst the two people that gave me the advice came down with cholera.
Maybe one answer is to develop a healthy profusion of gut bacteria (and perhaps nematodes too?). Mine got established under the influence of a medicinal nettle flower tea grown by the ruins of a moorish palace in Portugal whilst drinking clear running water from the mouth of a stone lion (later traced to the flushing overflow from an upstream communal village well).
To see something running clear should never be taken as an indication of its health. Stagnant black marsh water is probably safer as the marsh environment acts as a biofilter and the reducing conditions will have precipitated metals as sulphides into the underlying mud.
But prior to my inoculation with those Portuguese gut bacteria, it would take me 3 weeks to get used to “safe” chlorinated water from any new UK town I visited or re-visited, including London and my home town. It was a resilience that I acquired rather than one with which I was born.
Nowadays I still experiment with perishable protein that is well past its use by date and suspect that pushing that envelope has helped maintain my resilience.
Interesting story Dave. I personally feel that some people are over-cautious (ie. boiling for 10 mins), so like everything on this blog, I just provide some basic info and explain how I manage things – but in the end it’s up to each person to find what they’re comfy with.
Every cloud has a silver lining. The noise pollution and off-track degradation caused by dirt bike riders around 6ft track is pretty bad. But it was a group of them that found and rehydrated the two brits who had run out of gas they regarded as essential for boiling their water.
But if what he believes he can prove about uselessness of steripens is true, regardless of dubious claims by manufacturers for their diminutive devices, then perpetuating faith in them could be a problem. So I thought a word of caution was wise for those that worry.
However…Biggest ever scientific study (in eighties) about nasties in water was undertaken by US EPA. They concluded that more harm is caused by worrying about what might be in water supply than what was occasionally contaminating it.
Ha, that makes me laugh Dave. So much worry… but good story about the dirt bike riders. (Can’t believe I just said that!) 🙂
Ahhh, life giving water… Personally I prefer the Steripen Freedom – small, light and same battery charger cord as a mobile phone. Tablets in the first aid kit have never been used. Ahhhh, the Freedom!
Freedom is a good way of thinking about it, LBW. Who wants to spend a lot of time boiling water, when there are lighter, quicker and easier ways of dealing. We come into the bush to enjoy it, not boil the kettle 🙂
I use a sawyer mini filter, never had an issue. Mind you even filtering is over kill in Tassie’s streams 🙂
http://www.tiergear.com.au/11/online-shop/137-Sawyer-Mini-Water-Filtration-System
That looks like a nice small and light filter option… huh, I agree about Tassie streams though… whoop whoop happy dance.
After tasting the water sterilizing pills many back packer campers use in my state, I did some research on the issue of water sterilization. NOTE, I said STERILISATION not FILTRATION.
They are two different issues entirely. You can FILTER water until the cows come home, that will not make the water safer to drink. The tried and true method for generations has always been BOILING after FILTERING.
However, in practice at times, this proves to be problematical as in NO FIRE zones you cant light a fire, using your gas stove will reduce your supply of gas pretty quickly, so what’s the alternative ?
Firstly, I’d like to state that one creature in nature is highly susceptible to contaminants in water and will avoid bad water like the plague. They are FROGS. Any water that has FROGS or tadpoles swimming in it, is in my opinion, safe to drink after sterilization, I’ve found such water is not necessary to even filter.
Now, STERILISATION, ask yourself this question ; How did the early sea faring explorers sterilize their drinking water ?
Answer, SILVER, or more correctly, COLLODIAL SILVER, that is percentage of silver held in suspension in distilled water.
I’ve carried this around for many years and added the appropriate amount to my water allowed an hour or two for it to take effect and have never had an issue with it yet.
There are colloidal silver generators available over the Web these can be used to distil your own, or you can purchase it over the net, or from your nearest Pharmacy.
Using this, there is no taste whatsoever, I recommend it highly.
On another back pack camp trip, we had a young lady carrying RED CORDIAL, she didn’t drink any coffee, tea, or even chocolate, all she drank was this cordial infused water, needless to say, the 9 days she was with us, she showed no ill effects and her water source was the same as the rest of us.
Our source was RAIN PUDDLES left on rocky outcrops, these had tadpoles swimming in them, and after three days, the water became salty from evaporation making it undrinkable, the tad poles died.
One time we relied upon a soak for our water, and approaching the soak heard grunting, eventually saw this big fat black pig having a mud bath IN OUT WATER COURCE.
Needless to say, none of us were adventurous enough to try drinking that water after his bath. LOL.
Thanks for sharing your experience Eddy. Yep, there’s definitely a difference between steri and filtering. I’m not so bothered with filtering out a few bit of bugs or floaties in the water, just making sure it’s safe to drink. If desperate, I’ve been known to filter water through a sock or a bit of clothing before dropping a tab in it.
Oh and I love the piggy story – how rude of him 🙂 A few years back I heard that in the drought “Dead Goat Soak” in the Flinders Ranges, had a dead goat (or 2) in it, and therefore made it undrinkable.
Hi Eddy
I am not an expert on the subject nor have I done any research but you said…..
“You can FILTER water until the cows come home, that will not make the water safer to drink”
However the Sawyer water filter website claims…………
“Our proprietary hollow fiber membrane filters are small, portable, easy-to-use, reliable, inexpensive, and can last a decade without needing to be replaced.
Our filters are certified for ABSOLUTE microns making it impossible for harmful bacteria, protozoa, or cysts like E. coli, Giardia, Vibrio cholerae and Salmonella typhi (which cause Cholera and Typhoid) to pass through.
Just drink: no pumping, no chemicals, no waiting, no worries! Incredibly fast flow rate, simple to use, and each filter can be backwashed to extend its life. We’re so confident in our filter technology, most Sawyer Water Filters come with a 1 million gallon guarantee.”
https://sawyer.com/products/type/water-filtration/
Like I said, I really have no idea so I can only trust the above statement and hope its true??
This http://cid.oxfordjournals.org/content/34/3/355/F2.expansion.html is worthwhile to look at. At any reasonable altitude bring the water to the boil and anything that would hurt you will be dead by the time that you can drink the water.
Steripens seem to have been confirmed to be effective by a number of authorities. They probably don’t work near as well with dirty water.
Other than drinking from near campsites and huts there doesn’t seem to be much of a risk. There have been studies that show that the wilderness areas of America are lower in Giardia and Cryptospiridium than their water supplies. Not surprising as the water supplies often come from alpine and sub-alpine areas that are closer to the urban areas and therefore more heavily used and the chlorine treatment is not very effective against them.
What is a bigger problem in many areas is transference directly or indirectly by flies from toilets. Probably would get a lot more attention if someone was selling a $200 device rather than a few dollars worth of hand wash and care when eating.
That’s a handy table there Ken. I’m wondering if the 60-70degrees for 10mins, can translate to the 100degree (ie. rolling boil) for 1 min as per the WA Health recommendations?
Oh and interesting comment about the flies… reminds me of that time at Valentine’s Hut when the maggots and flies were crawling all over the seat… Hmmm, tasty!
I expect the 1 minute boil is the standard because it is nice and simple to remember and will kill Hepatitis A. One of the problems with the recommendations is that they will be designed to deal with situations like emergencies like floods where there will be high levels things like E coli and Hepatitis A from overflowing sewerage. In a wilderness situation Hepatitis A is unlikely to be a problem at all as it disappears from the environment in a week or two.
There is a lot about this on the web including academic articles, and it seems that once you take away the risk from being in a highly contaminated area there is very little risk. What worries me is being near huts where cross-country skiers may not be responsible with their toileting and poorly constructed pit toilets leaking into the ground water.
Yeah, good point about backcountry ski areas. I did the Kiandra to Kosci in Summer a few years back and drank most creeks without treating, without a problem. However, I was certainly a lot more cautious the closer I got to Kosci. After the maggot covered toilet seat at Valentines Hut one year, it always makes me think twice!
A fairly comprehensive analysis of this topic can be found at:
http://bushwalkingnsw.org.au/clubsites/FAQ/FAQ_Water.htm
The author is a CSIRO scientist who is extremely knowledgeable and sensible {IMHO)
Skibug
Yep, that’s a good article (although copyrighted 2002, so not sure if it needs to be updated?) and an example of how intense you can get with this type of thing. That’s probably a good article to start with if people are really keen to get into the nitty gritty… and isn’t that what’s in water? 🙂
Not so sure about that authors concern over too much iodine causing goitre. I was taught at school that Goitre (aka Derbyshire Neck) was caused by a deficiency (not excess) of iodine, especially in locations more remote from the sea. And that it was to overcome that common deficiency that iodine was added to table salt. But. then again, I am no expert on the matter.
Do you have any experience with filtered bottles? If they work well enough, it seems like they might be a decent, lightweight option.
Hey John, I’ve never used this method to clean water. Just feels like yet another gadget to take up space in my backpack, when I prefer to use a bladder system for drinking on the go and simply pop a tablet in or boil it. Less to carry 🙂
Millbank filter bags, as used by the Australian Army, are a lightweight “canvas” type “sock” that is extremely good at removing suspended solids, even very fine mud, from water. The bags are available from army surplus stores. This, combined with a pack of Aquatabs, is an efficient, lightweight, means of purifying water, assuming no dissolved nasties. (The filter bag weighs about 120 g.) Saves time and fuel compared with boiling. A few minutes work every evening was enough to keep our party of 4 supplied with water during a summer hike in the Snowy mountains. (You can never be too careful considering what brumbies are doing in the water.)
Thanks Ivan. Same principle as a coffee filter, so another nice step to go through. I’ve just come back from the Snowies too and I was more concerned about other bushwalkers poor wilderness hygiene than the brumbies 😉 Sick of seeing toilet paper lying around.
to add my five cents worth, my current set up is a steri pen “pure” (basically its a steripen freedom) and uses a USB recharge, my previous steripen was a “classic” gave good service and still operational but much heavier than the “Pure” 280g/75g, i also carry a small collapsible silicon funnel and paper coffee filters to filter out any solids.. i like cups of coffee (carry a “GSI” minimalist compact cook set) so can always boil some water if all else fails and have done well with that style of set up for several; years now..
Now as a further back up to everything, i suggest people read up on how to make solar stills, transpiration (i think thats the word) collection off foliage etc. as an emergency last ditch measure… 🙂
Thanks for the article (full of common sense) and the comments (full of facts and useful stuff!)
I’ve been using the Grayl filter for a while and find it to be effective, easy and lightweight. It claims to filter and sterilize 99.99% of baddies. No batteries required.
For my water purification in the bush i use a system of filter then UV or boil…
the filter system is a DiY one by using a coffee filter paper sitting in a collapsible silicon 1cup measure that i punched holes into (folds flat), after filtering i use my usb rechargeable steripen to sterilize the clear water, if i’m making coffee or heating a retort pouch meal in water i boil it for that without UV treatment…
another thing to note, consider switching from plastic to a single wall stainless steel wide neck bottle as you can place those directly onto a fire to boil water is required!!
as a side note.. all my electronics are usb rechargeable (steripen, torch, mobile/gps) and i have both a high capacity power bank (thank you Caro) and a solar panel.. i have the panel sitting on top of my pack on all walks trickle charging the powerbank (its not in the way and the sun is shining on your pack anyway so why wait till you stop?)