Generally speaking, you’ve really only got a 72-hour window to find a source of clean water in an emergency.
After that, severe dehydration sets in and your kidneys can start to shut down.
We’re going to cover 10 effective ways to purify water in an emergency so that you’ve got the knowledge to keep you and your family safe from water-borne illnesses when things get rough.
Caught Without Clean Water? Try These 10 Emergency Purification Tricks
If you are caught short without one of your emergency water filters you will need to get creative.
Below are some great ways to ensure you and your family have access to fresh water when times are tough.
1. Boiling the Water
If you find yourself in an emergency situation where you have easy access to water, fire starting materials, fuel and cooking implements, boiling is probably going to be the easiest method of purifying water.
By bringing water to a rolling boil for at least 1-3 minutes, you effectively kill most harmful bacteria and viruses that cause waterborne diseases.
If you’re boiling water at higher altitudes, where water boils at a lower temperature, try to extend the boiling time to around 3-5 minutes.
When boiling water, keep in mind that it’s not going to remove chemical contaminants or sediment, it just makes the water microbiologically safe to drink.
If you’re drawing water from a muddy puddle or ditch, you’re still going to be ingesting a lot of dirt, particulate matter and who knows what else if you don’t filter it after.
To get rid of particulate matter, consider filtering the water through a filter cloth or coffee filter (several times, if need be) before or after boiling.
2. Water Purification Tablets
Water purification tablets containing chlorine, iodine or chlorine dioxide, should be in everyone’s bugout bag, hurricane kit, and any other emergency preparedness inventory.
They’re lightweight and portable, which make them highly convenient for emergency situations.
They are so critical for purifying water worldwide, that the United Nations raises money to help pay for water purification tablet distribution to children and families in places like Sub-Saharan Africa.
These tablets are capable of killing bacteria, viruses and some protozoa like Giardia.
To use them, follow the specific instructions on the box they arrive in, but, generally speaking, you drop a tablet into a specific volume of water and wait the recommended period of time (typically around 30 minutes to 4 hours, depending on the contaminants and the type of tablet).
Bear in mind that these tablets can leave a chemical taste in the water, which you can improve by either aerating the water (agitating the surface) or adding flavoring agents.
Like boiling, water tablets are a good way to get rid of pathogens, but they won’t remove chemical pollutants or particulates, so pre-filtering might be necessary.
3. Portable Water Filters
Portable water filters are popular with hikers and preppers alike.
They work by physically trapping contaminants as water is forced through tiny pores in a filtration membrane.
Most modern filters are capable of filtering out bacteria, protozoa and sediment but they might not be as effective against viruses unless they have some kind of ultra-filtration capability.
Other models use activated carbon, which is great for getting rid of chemicals and heavy metals, which will improve the taste.
They’re simple to use and are good at filtering large quantities of water quickly, which means they’re great for both short and long-term emergency situations.
I would definitely want to have a portable water filter, such as a straw filter, to complement any other more temporary solutions like water purification tablets.
4. Solar Water Disinfection
Solar water disinfection, also referred to as SODIS, uses UV rays from the sun to kill pathogens in water.
It’s a simple, low-cost method that is particularly useful in places with a lot of sunlight. Maybe not the best method to try if you find yourself in an emergency situation in Washington State in November, but certainly something to keep in mind for Arizona in July.
To use solar water disinfection, fill a clear plastic or glass bottle with water and let it sit in direct sunlight for 6-12 hours (or up to 48 hours in cloudy conditions).
The idea is to let the UV rays from the sun, combined with heat generated inside the bottle, effectively deactivate bacteria, viruses, and protozoa.
Again, like boiling and purification tablets, this won’t get rid of chemical contaminants and particulate matter in your water, so pre-filter your water if it’s murky.
Obviously, the catch with solar filtration is that it takes a while. You need many hours (potentially even days) to use this method. Additionally, it’s not suitable for large quantities of water.
Here is the European Commission’s guide to safely using the solar disinfection method.
5. Chlorination
The Environmental Protection Agency states that you can use regular, unscented chlorine bleach (do not use scented, color-safe, or bleach with added cleaners) to disinfect water for drinking.
Here is there table laying out quantities and ratios:
The chlorine in bleach (like the chlorine in the water purification tabs we covered earlier), will kill most bacteria and viruses.
If your water is still cloudy or has a strong chlorine smell after 30 minutes, let it sit a bit longer or, as with the water tabs, consider adding some flavorants to the water to make it more palatable.
I’ve consumed water treated with chlorine tablets and it can taste like you’re drinking swimming pool water. But hey, a small price to pay in a life and death scenario.
6. Cloth Gravity Filtration
Cloth gravity filtration is a method by which water is allowed to soak through a piece of cloth (cotton, a bandana, or other absorbent fabric) into a container.
The cloth acts as the physical filter to remove large particles, sediment and debris from water. This is a method I have tested out myself (and yes, it really does work) and have seen numerous outdoor survival experts and YouTubers use to filter water.
Often they will repeat the process several times, allowing the water to filter through a few different stages to remove as many impurities as possible.
This method does not purify the water of bacteria and viruses, but it is a good first step before boiling or chemical disinfection. I just want to emphasize that this is not a standalone solution, but it is useful in emergencies when your water sources are murky or visibly dirty.
7. Solar Still
A solar still is a great way to purify water, especially in environments where access to clean freshwater is limited (e.g., you’re surrounded by saltwater or contaminated water sources).
It uses the natural evaporation and condensation processes to separate pure water from contaminants, including salt.
Here’s how it works.
Typically, it involves digging a hole in the ground, placing a container at the bottom to collect clean water, and then covering the hole with a transparent plastic sheet. You then place a weight at the center of the sheet above the container to create a low point.
As the sun heats the ground and the water beneath the plastic sheet, the water evaporates, rises and then condenses on the underside of the sheet. The condensation will then drip into your container, leaving behind salt, sediment and other impurities.
This is a great method if you are in desperate need of safe drinking water and there is no other option to get it. However, as with all solar methods, it’s a slow process.
You typically will only get a few ounces of water per day out of a solar still, depending on the sunlight and the size of the still. It also, of course, requires sunlight.
It could be the difference between life and death in an emergency scenario, though.
8. Urine Still
I first saw this method employed by Survivor Man, Les Stroud, in his Saharan Desert episode of his hit show Survivor Man, and was amazed by it.
I can’t say this is something I’m dying to try, but it does work and it can give you the gulp of life-saving water you need to keep yourself going and to ensure that you aren’t wasting any freshwater you have at your disposal.
It works very similar to a solar still. You start by placing urine in a container or pit beneath a transparent cover. You then place a small container inside the still to collect the purified water that has been separated from the urine via evaporation and condensation.
The vapor condenses on the plastic as the urine is heated and drips into the container you have set up for it, leaving behind salts, urea, and other impurities that don’t evaporate.
This is an emergency water purification method that I would probably consider to be a last resort, given how little drinkable water it yields and its dependence on the sun. I would also rather not drink water that used to be in urine unless I absolutely had to, for obvious reasons.
9. Improvised Charcoal Water Filter
I touched on the power of charcoal in the portable water filter section above, and you can improvise your own charcoal water filter in an emergency situation if need be.
Using charcoal (e.g., from a campfire) can help create an effective water filtration system that removes some impurities, bacteria and toxins from contaminated water.
The reason charcoal is so useful when it comes to purifying water is that it is very porous and has a large surface area, which makes it amazing at filtering out things you wouldn’t want to ingest.
If you want to know more about exactly how activated carbon absorbs impurities, check out this great article from Water Technology, a hub for companies and thought leaders in the water industry.
“Activated carbon has more useful surface area per gram than any other material available for physical absorption. A teaspoon of activated carbon has more surface area than a football field.” Wild.
To build an improvised charcoal filter you will need a container like a bottle or hollowed-out log and different layers of filtering material.
Start by crushing the charcoal into small pieces, and then create layers in your container–sand at the bottom, then a charcoal layer, and then gravel or small stones on top. Pour the contaminated water through the filter, allowing it to flow through each layer.
The gravel gets rid of large particles, the charcoal absorbs harmful substances, and the sand catches finer debris.
This method will not purify water entirely (since there are some bacteria and viruses it may not catch), but it will filter out particles, toxins and improves water clarity. As with most purification methods, it’s always a good idea to boil your water to make sure it is safe to drink.
10. Distillation
Distillation is the process of separating water from contaminants like salt, dirt and bacteria by turning it into steam and then condensing it back into liquid form.
It’s a great method to use when clean drinking water is limited and it’s cost effective. You don’t need any advanced equipment and you can do it with everyday items.
What you will need is:
- A heat source (a fire, a stove or a camping stove)
- A large container like a pot or kettle for boiling the water
- A smaller container to collect the distilled water
- A lid or cover to trap the steam
- A flexible tube or long straw to direct the steam (if you have one)
- Aluminum foil or plastic wrap for sealing the container off to make sure you aren’t losing any distilled water.
Fill your large container with contaminated water and place your smaller container (either inside or to the side, as above) to catch the distilled water. If you can, make sure it’s slightly elevated.
If the lid you have fits tightly over your two containers, then use that to trap the steam. You can also use aluminum foil or plastic wrap to cover the top and create a seal.
If you’re using a tube, attach one end to the lid or cover and then direct the other end into the smaller container to funnel the clean water into it.
