The dangers of drinking from natural water sources

and what to do about it

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(Here’s a picture of Jeremy the E.Coli bacteria and his friends, just waiting to be drunk from a water source near you)

It’s highly unlikely that you’ll find yourself in a situation where you are forced to drink from a natural water source, but in the event that it happens, it’s important to know exactly how dangerous the water would be to drink and what you can do to make it pure. Crystal-clear mountain streams can still contain enough bacteria to ruin the next couple of weeks, and some of the more dangerous bacteria can cause a whole range of more serious conditions.

Here are the most common natural water sources and how clean they are likely to be.

Forest stream

There is a group of bacteria called Coliform Bacteria that is naturally found in high concentrations within soil and plants. One of the things that makes forest water systems so dangerous is the high amount of fresh plant matter that enters the system, along with the waste of any wild animals that may be nearby or who die close to the stream.

(If you cup the water in your hand it will look crystal clear, but contains millions of tiny beings that’ll ruin your day)

Mountain Stream
The safest option on the list and one of the purest forms of natural water, so long as you collect the water from high up the mountain before it has the chance to pass through herds of animals. There are bacteria present in all natural water sources but it is often the lowest when it comes out of the ground at an elevated level. The big risk with this one is that underground water systems can often flow over harmful mineral deposits, but it is highly unlikely that there would be enough of something in the water to actually cause harm.

Lakes
Static water is the riskiest of them all, and it can often contain the Legionella bacteria that causes Legionnaires’ disease. During the warmer months, static water is often used as a breeding ground for various larva-laying creatures and this creates a massive amount of bacteria in the water. The other risk comes from the chance of animals peeing in the water, especially rats because the urine can cause a condition called Leptospirosis, also known as Weil’s disease.

Ponds
The smaller and dirtier version of the lake, ponds should always be avoided and have much higher chances of harboring diseases than lakes do. They are also normally in areas away from other water sources, making them a popular place for animals. Water from ponds should never be drunk unless professional-grade purifiers are available, such as a life straw, but should also be a last resort.

swamps and marshes
Literally the worst choice as the dangers of drinking from natural water sources increase drastically with static water. The high amount of plants and animals creates the perfect conditions for all kinds of nasty bacteria and should be avoided at all costs.

The sea
The only way to easily remove the salt would be through distillation, but even if you managed to remove the salt with a series of filters, seawater contains around 1 million bacteria per drop. Thousands of these will be of the type vibrios which is responsible for well over 90% of all seafood poisoning-related deaths.

In-land rivers
The main problem with inland rivers is they have had plenty of chances to collect animal waste and decaying plant matter. They are guaranteed to contain the Heterotrophic and Coliform bacteria groups, along with Weil’s disease, legionnaires disease, and a whole range of other potentially nasty things. All rivers around the country will be different, but the further inland they are, the higher the chances of developing something bad if you drink it.

How to Purify Water and its effectiveness

If you are forced to take water from a natural water source it’s important to never drink it directly, as even the smallest amount of purification could make a huge difference.

The first thing to do

If you have to use any of the methods below it’s important to always filter the water first, even if it’s through nothing more than a spare sock or piece of clothing. The amount of small pieces that will be removed will make the water easier to purify, and all of those tiny clumps of dirt will be home to clusters of potentially harmful bacteria.

Solar Purification

Ultraviolet light has the ability to kill most types of bacteria found in water, but there are certain types that have thick cell walls, such as the Cryptosporidium and Giardia groups. These can still be killed with solar rays but it takes a much higher intensity to do this, so the stronger the sunlight the higher the chances of the water becoming clean. To create a make-shift solar water purifier, all you need is something see-through like a plastic bag or water bottle, and then fill it with water you’ve filtered through something and place it in direct sunlight, preferably for several hours, keeping the lid on or bag tied for the process.

Packed cloth filter

This one involves filling a tube or plastic bottle with the bottom cut off full of pieces of cloth, or a single item of clean clothing stuffed inside. Dirty water is then poured into the top and slowly passes through the cloth, filtering out most of the pieces. If this method is used on its own then it should be a last resort, as the big bits will be removed but it will do nothing to get rid of the tiny micro-organisms that will cause you harm, though it’s better than nothing.

Moss and Charcoal filter

Cut the bottom off a plastic bottle and fill it with alternating layers of sphagnum moss and charcoal, then pour water into the wide end with the cap-end facing the ground. The moss has mild anti-bacterial properties, though they aren’t strong enough to do much, but when combined with the charcoal they do an excellent job of cleaning water. If the charcoal is ground fine enough it can remove a surprising amount of micro-organisms, though it’s far from being perfect.

Life Straws

These plastic tubes are filled with special filters that can remove even the tiniest germs. There are currently plenty of life straws for sale online that cost around £30, and claim to remove 99.999999% of bacteria, parasites, and microplastics, which if true is almost as effective as boiling.

Boiling

Without a doubt the most effective way to kill the bacteria and harmful things that can be found in natural water sources, though it does nothing to clean the water. The safest thing you could do in the wild with normal equipment would be to filter it through cloth followed by a rolling boil for at least 5 minutes.