A Practical Guide To Emergency Water Purification: What You Need To Know

After oxygen, there is nothing more necessary for human life than water. The human body can go without food for weeks or more, but without liquid intake,  a human would die within four days. Unfortunately, water sources can easily be contaminated with pathogens that cause diseases that exacerbate the effects of dehydration. Emergency water purification is a necessity if you find yourself without clean and purified drinking water.  This article will delve into the different ways of emergency water purification focusing on ones that use items commonly found in the home.

Different Ways You Can Purify Water

Emergency water purification is all about killing or filtering out any potential waterborne diseases that might be within the water you need to drink or use. The simplest form of emergency water purification is boiling or distilling the suspect water. Chemicals such as chlorine, iodine, and other similar chemicals can also be used to kill potential waterborne illnesses within the water, purifying it for drinking use. A third method involves the use of water filters, either makeshift or manufactured. All three of these methods have their pros and cons which will be examined below.

Boiling or Distilling for Emergency Water Purification

a kettle over a firewood

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Boiling water is the most common and simple way to remove disease-causing microorganisms from water. Many backcountry water sources are contaminated with Giardia, commonly known as beaver fever. Campers and hikers often boil water from these sources when they are in the backwoods. To kill any water-borne illnesses, boil your water vigorously for at least one minute. If you’re at an altitude of above one mile, boil your water for three minutes.

Boiling will only kill waterborne illnesses, but it will not filter out other impurities in the water. If you are concerned that the water source been contaminated with lead or other chemicals, boiling alone will not remove them. Another downside to boiling, but much less important, is that boiled water often has a flat taste. This is due to the lack of air in the water after boiling it out. Aerate your boiled water by pouring it back and forth between two containers and letting it sit for a few hours. Alternately, adding a pinch of salt per quart or liter will improve the taste; but don’t overdo it.

Distilling water is similar to boiling but takes it one step further, removing many other contaminants that simply boiling water will not. If you have the supplies to both build a water distillation system and to fuel it, this is one of the best long-term methods of emergency water purification. Distilling boils the water and then collects the steam, the water converted into gas form, and cools it to convert the steam back into its liquid state. The resulting liquid has been boiled to get rid of biological contamination, and the liquid-steam-liquid process leaves all other contaminates behind.

Chemical Emergency Water Purification

Most tap water is purified through the use of chemicals: usually chlorine. This chemical kills waterborne illnesses, making the water safe to drink if water-borne illnesses are your only concern. As with boiling, chemical emergency water purification methods will not get rid of heavy metals or other chemical contaminants in the water. There are many chemical-based emergency water purification tablets on the market, and they are cheap and effective.

Another positive to the chemical method of purification is that they preserve your fuel. In an emergency situation, fuel for fires can be at a premium. The more fuel you used to purify your water, the less you will have for other uses.

The biggest downside to chemical-based water purification method is that you need the chemicals in order to purify your water. In an emergency situation, especially one that drags on, it is possible to run out of your iodine, chlorine, or other chemicals. Some of these also leave a distinct aftertaste, but safe drinking water is always more important than tasty drinking water in an emergency situation.

Despite the drawbacks, emergency water purification tablets should be a vital part of any emergency preparedness kit. Sure, in a long emergency you might run out, but they are cheap and take up little space. Even in a long-term emergency situation, they could save your life as you work out a distillation system for the long haul.

Water Filters for Emergency Water Purification

Water filters use a variety of different methods to remove contaminants from water. In essence, it is easiest to think of them as a net that captures contaminants in the water and prevents them from moving through the filter. When it comes to emergency water purification, the biggest issue is how big the holes in the nets of the water filter are.

Most commercial water filters used in the home are designed to filter out larger contaminants such as heavy metals, protozoa, and even bacteria. Unfortunately, viruses are much smaller, and most microfiltration devices are not effective at removing viruses. Look for ultrafiltration water filters as they are moderately effective at preventing viruses from passing through them.

Water filters also have the same downside as chemical emergency water purification methods: water filters wear out over time with repeated use. This makes them less than ideal in a long-term emergency survival situation. That said, there are several small personal size emergency water purification filter systems that can be of great utility for shorter-term emergencies, so they are a good addition to your emergency kit.

Is There a Need for Specific Chemicals When Purifying Water?

As discussed above, chemicals can be used for emergency water purification purposes, but they are not a necessity, especially if you have the fuel and means to boil or build a distillation device. There are several household chemicals that can be used for emergency water purification needs. The most common of these are bleach and hydrogen peroxide.

If you find yourself in need of emergency water purification, add two drops of bleach per quart of water. With hydrogen peroxide, 2 mL per gallon of water will suffice for emergency water purification needs in most cases. If the water is known to be more contaminated, add more hydrogen peroxide.

Emergency Water Purification 101

If you ever find yourself in an emergency situation and need to use an emergency water purification method, follow the directions in this section to go through the basics of the boiling and distilling methods.

Collecting Water in an Emergency

clean and clear river

Image Source: Pixabay.com

Most places have access to some sort of water source that only needs to be purified in order to be used for drinking water. As part of your emergency preparation, look at the different possible water sources near your home to determine if you will have access to water that can be purified should an emergency arise.

If you live next to a lake or other freshwater source, this should be easy. If you do not, you will have to think about collecting water. In an emergency, the tap water system might fail. Collect as much water as possible through the tap before this happens if an emergency strikes. For example, if an earthquake hits, once it is safe to move after the shaking fill your bathtub full of water, bottling as much as you can. This will ensure that you have a water supply for later use should the taps fail.

For those that live on the coast or on sea islands, saltwater can be turned into freshwater by distilling it. Once the water evaporates, it leaves the salt behind as well as most other contaminants. Simple methods of home water distillation will be covered in the next section and can work for desalination. As with all distillation methods, this requires fuel unless you are using the sun, but that has its own limitations depending on your climate.

Build Your Own Distillation System

For optimal emergency water purification, a distillation system is the best method, and basic distillation systems can be made at home with readily available items. A more complex system can be constructed before an emergency hits as well, requiring only containers and copper tubes.

Basic Home Distillation

For the basic home emergency water purification distillation method, you will need a large pot with a lid, a heavy-bottomed drinking glass, and a fuel source. Pour the water to be decontaminated into the pot and place the heavy-bottomed drinking glass in the center of the pot, but make sure that the water level in the pot is not higher than the drinking glass. Put the lid on the pot upside down and place it on the fuel source. As the water in the pot boils the steam will condense on the lid, collecting at the center and dripping into the waiting drinking glass.

This can be done using solar energy as well. Collect water into a large bowl and place a smaller bowl in the center of that bowl. Cover tightly in plastic and place a rock on top of the plastic to weigh it down to let any condensation drop into the smaller bowl. Place this in the sun and let it do the work for you.


Emergencies happen, and when they do, safe drinking water can be hard to come by. Should disaster strike, use the information in this article to ensure the water you drink is safe.

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Hi I'm Jamie, teacher and owner/chief contributor at waterfilteranswers.com. We strive to bring you the most informative water filter reviews in the most intuitive and user friendly way. Besides offering advice on the water filter to suit your needs, we also post topical articles on water pollution and the environment. Stay connected and follow us on, Facebook, Twitter, Google+ and more!

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