You’re stuck in the woods, supplies are running low, and the only source of water is a stream running along the edge of the forest. Can you dip your head in and a take a drink? Not a good idea, the water may contain toxic, microscopic organisms that can make you ill, or worse.
Although there is not a 100% fool-proof way to purify water in a situation like this, following are some techniques that will you give a fighting chance to eliminate many, if not most of the harmful pathogens found in natural sources of water.
If you required clean water and had access to slightly more elaborate equipment and a power source (even solar power), there are other methods such as Distillation, Desalination and Reverse Osmosis.
For now, we’ll cover techniques aimed at people in precarious situations such as camping, hiking, and backpacking when things don’t go as planned, and you’re limited to basic gear or natural ingredients.
Assuming you have means to start a fire (which should not be difficult if you ventured out with the bare necessities), boiling water can eliminate up to 99% of dangerous microorganisms. Ensure you heat water to a minimum of 149 degrees Fahrenheit (65 degrees Celsius) for at least 30 minutes.
Ultimately, you want to see bubbling as an indication the water has reached an effective temperature (bubbling occurs at 212 degrees Fahrenheit, or 100 degrees Celsius).
At this temperature, let the water bubble for at least 5 minutes, remove from fire, let cool and drink.
Chlorine, a treatment used in public water supplies to kill a large variety of microbial waterborne pathogens, including those that can cause typhoid fever, dysentery, and cholera can also be used in dire situations, keeping in mind there is a lag between addition and effectiveness. 2 drops of household bleach per 1 quart (litre) of water is the recommended mixture, keeping in mind it takes varied amounts of time to kill different germs. It’s best to cover and let stand for 30 minutes and until there is a slight chlorine smell, otherwise repeat.
Iodine, although not recommended for extended use, can also disinfect warm water using a mixture of 6 drops per 1 quart (litre) of water. Let stand for a minimum of 30 minutes unless disinfecting cold water – it will need to stand for several hours.
In both uses, the mixture will likely need to be stronger if the water is murky.
Both chlorine and iodine, as well as other purification concentrates are available in tablet form with accompanying directions.
Squeeze Filters & Portable Water Filter Straws
Squeeze water filtration systems are highly effective, and one of the preferred methods of water purification, especially among outdoorsmen (and women).
The filters’ pours are designed small enough to allow water through, but too small for harmful bacteria (like salmonella), protozoa, or cysts like E. coli, Giardia, Vibrio cholerae, and Salmonella typhi to pass through.
Sawyer, a Safety Harbor, Florida company is well known for its line of water filtration products, including highly regarded portable devices that deserve a pocket in every backpack.
Although cloth filtration does not remove many of the pollutants and pathogens that you don’t want, it’s an effective method to remove larger particles from water. Again, don’t rely on cloth filtration to remove all dangerous germs and bacteria, but if you repeat the process multiple times, you can eliminate visible particles (and certain germs) before using a proper purification method.
Although these visible particles are not only unwanted, there is a chance they have bacteria attached to them which is good enough reason to eliminate them prior to purification.
If you’re stranded in the wild, you may not have the luxury of preferred (tightly woven) cloth, but any cloth will be better than no cloth.
Stone, Sand & Charcoal Filtering
Create a makeshift filtering system with an empty 2-quart (litre) pop bottle, charcoal from your campfire, sand (or very fine dirt), and stones.
This technique is especially effective for murky or cloudy water.
Cut off the bottom of the bottle, either put a stone in the neck (spout) of the bottle, or secure cloth around the spout, drop in a third charcoal, a third sand, and a third stones.
Each layer plays in role in the filtration. First, the stones catch larger particles, next, the sand catches smaller particles, and third, the charcoal aids in purification but should not be relied upon as a proper purification method.
Devise a way to hang the bottle upside down and begin pouring your water into the large opening on the bottom of the bottle. Don’t catch the initial water coming out, it will contain small amounts of sand and charcoal.
As the water appears to lighten in color (becomes clearer), you can start catching it and running it through your filter again. Do this enough times and you will eventually end up with clear(er) water.
It is important to understand the result will be filtered water, not purified water. You must still purifier the water to help eliminate dangerous germs. The simplest way to purify the water, assuming you have the means to start a fire, will be boiling it.
There are times when loosing access to clean water is unavoidable, but there are ways to prepare before heading out on your next camping or hiking adventure.
On most camping trips, you’ll have a vehicle close by, there may be running water at the campsite, the general store may sell ice and water, but if you’re camping in the woods, access to clean water will be limited to what you bring, and then to alternative methods.
In other words, make sure you bring the necessary gear to purify water, whether it’s a way to start a fire coupled by a metal pot for boiling, chemical treatments, squeeze filters or portable filtering straws, plus some cloth for filtering.
Hiking, Backpacking and Backcountry adventures require more consideration. First, make sure you bring enough clean water for the duration of your trek, taking into consideration the terrain and how demanding it is, expected temperatures, etc.
It’s prudent that you have a backup plan for clean water in the vent you were to lose your way or get injured. In other words, you’ll want to have light-weight water purification gear in your backpack.
When the amount of water you bring is limited to how much you can comfortably carry, it’s important to know you are able to prevent dehydration.
Don’t forget, death can occur in 72 hours without water, sooner in physically demanding situations or extreme temperatures.