When you find yourself in a survival situation, one of the most essential needs is access to clean, safe drinking water. Without it, staying hydrated and healthy becomes a daunting challenge. Fortunately, several effective methods exist to purify water, each with its own advantages and best-use scenarios. Whether hiking through the wilderness, camping in remote areas, or preparing for emergencies, knowing how to purify water can make all the difference.
In this post, we’ll briefly describe various water purification methods suitable for survival situations. We have in-depth posts on each method that you can access via the links in this post.
Choosing the right method depends on several factors, including your environment, the type of water source, and having a backup plan if your primary method fails. By understanding and combining these methods, you can ensure that you always have access to safe drinking water, no matter the circumstances.
1. Boiling
Method:
Heat water to a rolling boil for at least one minute. At altitudes above 2,000 meters (6,562 feet), boil for at least three minutes.
Pros:
Highly Effective: Kills most pathogens, including bacteria, viruses, and parasites.
No Special Equipment Needed: Only requires a heat source and a container.
Widely Accepted: Recognized as one of the most reliable purification methods.
Cons:
Fuel Requirement: Requires a fuel source (wood, gas, etc.), which may be scarce.
Time-Consuming: Takes time to gather fuel, start a fire, and wait for the water to boil and cool down.
Does Not Remove Chemicals: Ineffective against chemical contaminants.
Tips:
Use a covered pot to reduce heat loss and boiling time.
Pre-filter cloudy water through a cloth or coffee filter to remove sediments.
In cold climates, keep boiled water in insulated containers to retain heat.
You can learn more about boiling water for survival here.
2. Portable Water Filters
Method:
Use devices like straw filters, pump filters, or gravity filters to mechanically remove contaminants from water.
Examples: LifeStraw, Sawyer Mini, Katadyn Hiker Pro.
Pros:
Portable and Lightweight: Easy to carry in a backpack.
Immediate Use: Provides clean water instantly.
Effective: Removes bacteria, protozoa, and some filters can remove viruses.
Cons:
Maintenance Required: Filters need regular cleaning and eventual replacement.
Limited Lifespan: Each filter has a maximum volume it can purify before it needs replacement.
May Not Remove Viruses: Some filters do not remove viruses, so combining with chemical treatment may be necessary.
Tips:
Carry spare filters or pre-filters to extend the lifespan of your main filter.
Avoid freezing temperatures as water inside the filter can freeze and damage it.
Backflush the filter regularly to maintain flow rate and effectiveness.
You can read more about the different portable water filters here: Portable Water Filters: Your Best Friend in the Wilderness
3. Chemical Purification
Method:
Add chlorine dioxide tablets, iodine tablets, or a few drops of liquid bleach to water and wait for the prescribed amount of time.
Examples: Aquamira, Potable Aqua.
Pros:
Lightweight and Compact: Easy to carry a supply of tablets or drops.
Effective: Kills bacteria, viruses, and protozoa.
Simple to Use: Minimal effort required to treat water.
Cons:
Unpleasant Taste: Chemical treatment can leave an aftertaste.
Waiting Time: Requires a waiting period (usually 30 minutes) for the chemicals to work.
Less Effective in Cold Water: Cold temperatures can slow the chemical reactions.
Tips:
Store chemicals in a cool, dry place to maintain their effectiveness.
Pre-filter water to remove sediments and improve taste.
In very cold water, warm the container in your hands or by a heat source before adding chemicals.
Learn more about chemical water purification here: Chemical Purification: Light and Effective Water Treatment
4. Ultraviolet (UV) Purifiers
Method:
Use handheld UV devices to expose water to UV light, which inactivates pathogens.
Examples: SteriPEN.
Pros:
Quick and Easy: Purifies water in about 90 seconds.
Effective: Kills bacteria, viruses, and protozoa.
Portable: Small and lightweight devices.
Cons:
Requires Batteries: Dependent on battery power, which can run out.
Does Not Remove Chemicals: Ineffective against chemical contaminants.
Needs Clear Water: Cloudy or muddy water reduces effectiveness.
Tips:
Carry extra batteries or a solar charger.
Pre-filter water to ensure it’s clear before using the UV purifier.
Keep the device dry and store it in a protective case to avoid damage.
To learn more about UV water purifiers see: Ultraviolet (UV) Water Purifiers: Quick Water Treatment
5. Solar Disinfection (SODIS)
Method:
Fill clear plastic bottles with water and expose them to direct sunlight for at least six hours.
Pros:
No Special Equipment: Utilizes natural sunlight and available plastic bottles.
Effective: Kills bacteria, viruses, and protozoa.
Cost-Free: No ongoing costs once you have bottles.
Cons:
Time-Consuming: Requires several hours of sunlight.
Weather Dependent: Ineffective in cloudy or rainy conditions.
Limited Volume: Suitable for small amounts of water.
Tips:
Use clear PET plastic bottles, as they are most effective for SODIS.
Place bottles on a reflective surface (e.g., aluminum foil) to enhance UV exposure.
Ensure water is clear; pre-filter if necessary to remove turbidity.
Learn more about SODIS here: Solar Disinfection: Harnessing the Sun for Clean Water
6. Activated Charcoal
Method:
Use activated charcoal to adsorb chemical contaminants and improve taste. Often combined with other filtration methods.
Pros:
Improves Taste: Removes odors and improves water taste.
Removes Chemicals: Effective against some chemical contaminants.
Easy to Use: Can be used in portable filters or DIY setups.
Cons:
Does Not Kill Pathogens: Needs to be combined with other methods for complete purification.
Limited Lifespan: Charcoal needs replacement after absorbing contaminants.
Tips:
Use in combination with mechanical filters or boiling for comprehensive purification.
Replace charcoal regularly to maintain effectiveness.
Store charcoal in a dry, airtight container to prolong its life.
Learn more about how you can use activated charcoal here: Activated Charcoal: Enhancing Water Quality
7. Improvised Filtration
Method:
Create a basic filter using layers of sand, gravel, and charcoal in a container like a plastic bottle or bucket.
Pros:
Natural Materials: Can be constructed from available natural resources.
Removes Particulates: Effective at removing sediments and some pathogens.
Cons:
Labor-Intensive: Requires time and effort to construct and maintain.
Less Effective: Not as reliable as commercial filters for pathogen removal.
Tips:
Combine with boiling or chemical treatment for safer water.
Regularly clean and replace filtering materials to maintain effectiveness.
Pre-filter water through a cloth before using the improvised filter to extend its life.
For more deatils on how to build your DIY water filter go here: Improvised Filtration: DIY Solutions for Clean Water
Tips for Choosing the Right Method:
Selecting the right method to purify water is key to ensuring you have safe drinking water. Different environments and water sources present unique challenges, so it’s necessary to understand the pros and cons of each method and how they apply to your specific circumstances. Here are some tips to help you choose the best water purification method for your needs.
Consider the Environment
The environment you’re in plays a significant role in determining the most effective water purification method. In cold climates, boiling or chemical treatments might be more reliable. Boiling water is a straightforward method that doesn’t rely on external conditions, making it highly effective in cold weather. Just remember to boil the water for at least three minutes at high altitudes to ensure all pathogens are killed. Chemical treatments, such as chlorine dioxide or iodine tablets, are also effective in cold climates, though you might need to extend the contact time to ensure thorough disinfection.
In contrast, if you’re in a sunny area, Solar Disinfection (SODIS) can be very effective. SODIS utilizes the sun’s UV rays to kill pathogens, making it an excellent choice for warm, sunny environments. Simply fill clear plastic bottles with water and expose them to direct sunlight for at least six hours. This method is particularly useful in regions where fuel for boiling is scarce, and it’s both cost-effective and easy to implement.
Water Source
The type of water source you have access to also influences the choice of purification method. Clear, fast-running water is generally safer and easier to purify than stagnant or muddy water. For instance, portable water filters work exceptionally well with clear water, removing bacteria, protozoa, and sometimes viruses. Devices like the LifeStraw or Sawyer Mini are ideal for drinking directly from streams and rivers.
However, if you’re dealing with stagnant or muddy water, pre-filtering is crucial to remove sediments before using other purification methods. Improvised filters made from sand, gravel, and charcoal can help clear up murky water, making it easier to purify. After pre-filtering, methods like boiling, chemical treatments, or UV purifiers can be applied to ensure the water is safe to drink.
Backup Options
No matter how reliable your primary water purification method is, it’s always wise to have a backup plan in case it fails or becomes unusable. For example, if you rely on a UV purifier like the SteriPEN, carrying extra batteries or a portable solar charger ensures you can always power the device. Similarly, if you’re using chemical tablets, having a surplus supply or an alternative chemical purifier can save you in a pinch.
Boiling water can serve as a universal backup method, as it doesn’t depend on specialized equipment or supplies beyond a heat source and container. Even in the worst-case scenario where you have no equipment, knowledge of improvised filtration techniques can be invaluable. Learning to construct a basic filter using natural materials like sand, gravel, and charcoal can provide a temporary solution until you find a more reliable method.
By understanding the strengths and limitations of each method, you can make good decisions that ensure you have access to safe drinking water in any survival situation. Whether you’re in a cold climate, a sunny area, or dealing with murky water, having multiple purification strategies and backup plans will help you stay hydrated and healthy.