Humans cannot survive without water, but it’s necessary for water from most sources to be purified before drinking. This is a matter of safety, for water from untrusted sources could be contaminated with various microorganisms or possibly industrial effluents. The first thing is finding a source of water and determining if it’s actually useable or not. This can sometimes be a challenge in extreme circumstances, particularly in cases of natural disasters and the like. Even if you’re on a routine camping or hiking trip, unforeseen situations can arise where you need to find a source of water. Beyond that, it’s not feasible to take large amounts of water with you if weight is a concern – which makes it necessary to carry something for making water potable. If you can’t figure out how to filter water, you run the risk of succumbing to dehydration or to various waterborne illnesses.

Water from unknown or untrusted sources could have any number of contaminants in it, which would be plainly idiotic to drink without undergoing purification. The source of contamination can vary, and certain methods are more effective at removing certain contaminants than others. Microorganisms can be killed using several methods, while issues like turbidity will require filtration of some kind. Industrial chemicals, fertilisers, and metal contamination are trickier issues to deal with, and there are particular methods for purifying water that you know has a particular source of contamination.

How to find water

The source of your water matters a lot, which in more extreme situations can be even more difficult.You should avoid standing water if possible, and go for the clearest source that you can find. Do not assume that water is potable without treatment just because it’s clear – it can still contain any number of contaminants that could make you very sick If it’s not possible to find clear water, it will be necessary to treat the water for both pathogens and for turbidity if not for other forms of pollution. Some methods might be suitable for both solid particulate matter as well as pathogens, while other methods will only be useful for one or the other.

If you’re lost in the wilderness, it may not be so difficult to find water depending on your environment. Forested environments may prove to have sources of potable water, even if they aren’t immediately obvious. For instance, grape vines contain some amount of potable water – which can be useful if you happen to get lost hiking and need an immediate source of water.

How to filter water

The following are 10 different methods that you can try for purifying water so that you can drink it. Not all of them will work in every situation, so use your discretion in determining which is best for the situation at hand.


One of the oldest and most widely used methods of water purification is boiling, which is effective at killing microorganisms in the water. That being said, the water may still have a taste, may still be turbid, and may still have chemical traces depending on the source you’ve used. Use this in combination with other methods if necessary. Boiling water is a very simple process if you have the right equipment, but in extreme situations it may become necessary to improvise.

If you’re on a campsite with everything else but no drinking water filter, boiling becomes a feasible option to kill any pathogens that you might be concerned about. While boiling is effective for killing microbes, it may be less feasible in certain circumstances due to the lack of any suitable container for boiling. In this case, it will be necessary to look for other alternatives for making water safe to consume.

Reverse Osmosis

One popular method for purifying water at home is reverse osmosis filtration, which applies pressure to remove solid particles including salts. As such, it can be used for desalinisation as well as filtering out the added fluoride from your municipal water supply.

Reverse osmosis typically utilises filter systems, whether attached to your tap or in a specialised pitcher. Many of these systems are quite affordable and simple enough to be suitable for home use, so you should consider this if you’re looking for a basic drinking water filter because you don’t like the water that comes out of your taps. There are some reverse osmosis systems which are portable enough to carry if you’re looking for a water filter for camping.

Chemical Treatment

Chemical treatment is used by many municipal water supplies, mostly in addition to other methods for treatment. This will kill off many microorganisms present in the water, but doesn’t prove effective in getting rid of chemical pollutants or turbidity.

Chlorine is one chemical that can be used for purification in emergency circumstances, with most chlorine bleach containing around 5% chlorine. This is an effective method for almost immediately killing off most micro-organisms in water as bleach is a heavy oxidant, but be careful to not add too much. You should add around 4 drops of bleach per quart/liter.

Another basic chemical purification method utilises iodine, though this will take a bit longer than if you’re using chlorine. Since iodine is frequently found in first aid kits, this method of water purification could still be useful in an emergency situation where you’re somewhat away from civilisation. Iodine kills an array of commonly found pathogens, but not all of them – so you should still be careful. To use iodine, leave the water to warm in the sun for some time and add between 5 and 10 drops per quart/liter, depending on how clear the water is. Alternatively, you can use iodine tablets for water purification (available at most camping stores). Leave the water to sit for at least 30 minutes before drinking or using.


Distillation is effective at removing many contaminants from water, as well as for the purposes of desalinisation. This process involves heating the water so that it evaporates and collects in a pipe leading to another container, thus removing many impurities that can be found in water. Since water from unknown sources can contain dangerous pathogens such as E. coli, distillation provides a viable solution for making potable water in a desperate situation.

Traditional stills require a sealed pot set up over a heat source, with a pipe at the top for steam to collect. This pipe typically passes through water for the sake of cooling, and leads to a vessel for collecting the distilled water/liquid. Heating the water should kill any pathogens in it, and distillation will filter out any impurities in the water. It may become necessary to distill water multiple times in order to produce completely clean water, so don’t There are solar distillation methods which could be useful in any outdoor situation, be it camping or getting lost in the wilderness. You can buy a kit for solar water distillation, but it’s also possible to fashion one out of a few readily available components that you should be able to scrape together. A solar still is also suitable for the purposes of desalinisation, so the aforementioned kits are a must have if you’re planning to go to sea anytime soon.

A solar still contains two troughs: one for the contaminated water, and an empty one for collecting the distilled water. A piece of glass is placed at an angle over the contaminated water trough, angling down into the collection trough for the distilled water. In order to increase the amount of energy absorbed from the sun, it’s useful to use a black trough for the contaminated water (or to paint it black). This method is basically taking advantage of the processes of evaporation and condensation, and beyond setting up a solar still and adding the water it requires little effort and no additional filters or technology.


While you can certainly desalinise water using distillation or reverse osmosis, there are other ways that could prove more practical if you find yourself stuck at sea or on a deserted island somewhere and don’t have potable water. There are portable desalinator products available, which you should take to sea with you. These include solar stills as well as filter systems and other setups, though the former may be the easiest to take to sea with you.

Cloth Filtration

If there is a lot of particulate matter present in the water, cloth filtration becomes an option. This will not filter out any pathogens or pollutants, so you should only use this method with relatively clean water or prior to purifying the water through other means. You can also set up a more complex filtration system using roots and cloth, which will give you clear water that’s still not necessarily safe to drink. While cloth filtration might not make for the ideal drinking water filter, it will still remove some of the impurities.

UV Water Purification

Ultraviolet light stops microbes from reproducing, which vastly reduces their potential for harm. The drawback of UV purification is that you should not expose the water to sunlight for any length of time, or else there’s a chance of the microbes reactivating and thus becoming harmful again.

You can buy UV water purification systems, some of which are small and portable enough to carry with you. While you will still need a power source to charge it, there are UV water purification pens that you can charge using a normal USB connection. These are a great idea to keep on hand (and keep charged), should you find yourself in a situation where the only potable water source is subject to microbial contamination.

Slow Sand Filters

Slow sand filters produce relatively clear water free of pathogens, taste, and odour. They do not necessarily remove all bacteria from the water. This might not be the most practical setup for a water filter for camping, if you need something for short-term use. It may still be an option if you’re stuck in the wilderness for a long time and need a long-term solution to water filtration, or if you’re building a camping site.

Slow sand filters are built with a layer of gravel on the bottom, upon which course sand is placed. Finer sand is place on top of this, and the water is allowed to flow through from the top. The subsequent layers filter out any sand particles in the water, while many contaminants are filtered out when they pass through the biofilm layer that grows in the top. The addition of charcoal will filter out any flavours or odours present in the water.

Stone/Ceramic Filtration

Stone and ceramic filters for drinking water have existed for centuries, and are still commonplace in many parts of the world. These include jempeng stones and various ceramic filters, usually of the type using a container with two separate parts. In most ceramic filters, contaminated water is placed in the upper portion and slowly collects in the lower one, passing through a ceramic filter. A jempeng stone filter works in a similar manner to ceramic filters, with the water being filtered through porous stone in order to remove any turbidity or other particulate matter. If you’re looking for a great water filter for camping, you might consider a ceramic or jempeng stone setup.

How to Store the Water After Filtration

Once you’ve actually purified the water for drinking, you need a safe way to store it so that it doesn’t get contaminated all over again. If you have any clean containers or bottles with you, this is the obvious answer. It’s generally better to allow containers to thoroughly dry in the sun if that’s at all possible in your circumstances, so as to avoid contaminating your freshly potable water with waterborne pathogens or other pollutants. Nearly anything that you can find will do, but it’s better if your water is protected from sunlight and from being left open. Open water containers can become standing water pretty quickly, risking recontamination as well as eventually becoming a breeding grounds for mosquitoes. If you decontaminated you water using UV purification methods, it’s absolutely essential that the treated water is not exposed to any source of light for any duration of time, or else the deactivated pathogens will be reactivated and begin reproducing once more. Water is essential for human survival no matter what the circumstances, and becomes all the more important in extreme circumstances where there’s a real potential for dehydration to occur. Knowing or not knowing how to filter water before any outdoor trip or seafaring excursion can be a matter of life or death, so be sure to look over the above options for making water potable and try to plan ahead. In an emergency situation, you may be able to use some of these methods to build your own setup so that you neither die of dehydration nor of some waterborne illness contracted from drinking contaminated water.

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