Simple Water Purification Methods for Safe Drinking Outdoors

hand holding water in pond

Unsafe water can cause health problems like diarrhea and stomach pain. Our blog post explores ways to purify lake water for safe drinking, crucial for hiking, camping, or traveling. These methods are valuable for outdoor enthusiasts and casual hikers.

1. Boiling Water

Boiling kettle on a multifuel burner with a mug in the forest.

Boiling is one of the most effective ways to purify water. It’s a simple, no-frills method that kills bacteria, viruses, and parasites that cause waterborne diseases. Boiling water is lethal to many microorganisms, like Cryptosporidium and Giardia parasites. It’s important to know that boiling kills germs but not chemicals in water.

Steps to properly boil water for purification

You can follow these steps to boil water for safe drinking:

  1. Start by collecting water from your source. Ensure that the container you’re using to collect the water is clean or disinfected.
  2. Place the collected water over a heat source. If you’re in the wilderness, this could be a campfire or a portable gas stove.
  3. Bring the water to a full rolling boil and maintain the boil for at least 1 minute. If you’re at elevations above 6,500 feet, extend the boiling time to 3 minutes to account for the lower boiling point at high altitudes.
  4. After boiling, let the water cool naturally without adding ice. To improve the taste, pour the cooled boiled water between two clean containers a few times. This will add oxygen to the water.

2. Water Purification Processes

House water filtration system. Osmosis deionization system. Installation of water purification filters under kitchen sink in cupboard. Clear water concept. Small sharpness, possible granularity

Water treatment processes are generally complex procedures that require advanced equipment. But don’t panic – some simplified versions of these processes can be used in a pinch when you’re out in the wilderness.

The water purification process includes key stages necessary for providing safe and clean drinking water. These stages are as follows:

  • Coagulation/Flocculation: The initial stage in water purification involves introducing a chemical coagulant to bind with dirt and other particles, causing them to either settle at the bottom or rise to the surface.
  • Sedimentation: Following coagulation/flocculation, water enters a sedimentation tank, where gravity causes heavier particles to settle at the bottom. This results in the formation of sludge that is subsequently removed, leaving clearer water above.
  • Filtration: The clear water from sedimentation is filtered through layers of sand, gravel, and charcoal to remove smaller particles. Portable water filters can be used in the wilderness, but note that most portable filters do not eliminate bacteria or viruses.
  • Disinfection: The filtered water is disinfected with chlorine or ultraviolet light to eliminate bacteria, viruses, and parasites. Correct use of chlorine dioxide tablets can effectively combat Cryptosporidium.
  • Sludge Drying: The sedimentation-derived sludge is dried and appropriately disposed of. This step is not usually applicable to wilderness applications but is crucial in extensive water treatment procedures.
  • Fluoridation: Fluoride is added to water in certain areas to prevent tooth decay. However, this method is not suitable for wilderness scenarios.
  • pH Correction: Lime is added to treated water to adjust its pH and hardness, ensuring its safety for consumption. In a wilderness setting, pH correction is usually not done due to the absence of required equipment and supplies.

3. Wood Filters

Pile of natural activated carbon scattered isolated on white background. activated carbon is used for effective applications in adsorption, removal of pollutants, water treatment, and energy, etc.

A wood filter, more commonly known as a charcoal filter, is a simple yet effective way to purify water. Charcoal has long been used as a natural water filter because it can effectively absorb impurities from the water, including certain types of bacteria. It works by adsorption, trapping contaminants in the small pores of activated carbon.

Steps to create and use wood filters in the wild

Crafting a wood filter in the wilderness might be a bit challenging, but it’s doable. Here are the steps:

  1. First, you’ll need a container, like a plastic bottle or a hollow bamboo segment. Cut off the bottom to create a funnel.
  2. Place a layer of clean pebbles or small stones at the bottom of the container. This will help to hold the other materials in place.
  3. Add a layer of sand on top of the pebbles. This will filter out larger particles.
  4. Next, add a layer of charcoal. If you don’t have activated charcoal, you can use charred wood from your campfire. Make sure it’s cooled before you use it.
  5. Finally, add another layer of sand and then another layer of pebbles.
  6. Pour the water slowly into the top of the filter and collect it at the bottom.

This method should only be used as a last resort, as it doesn’t guarantee the removal of all harmful organisms and chemicals. It’s always better to boil the water after filtering it to ensure that it’s safe for drinking.

4. Hot Rocks

The hot rock method is an ancient technique for boiling water when no metal container is available. The idea is to heat rocks in a fire and then place them in the water to cause it to boil. Boiling the water kills most microorganisms, making it safer to drink. However, this method also has its limitations.

Steps to heat rocks and use them to purify water

If you find yourself in a situation where you don’t have a pot or any other container to boil water in, but you have access to fire and rocks, you can follow these steps:

  1. Find several medium-sized rocks. Avoid using rocks from the water as they might explode due to trapped moisture when heated.
  2. Heat the rocks in your fire for about 15-30 minutes until they are red hot.
  3. Using tongs or two sticks, carefully remove the hot rocks from the fire.
  4. Drop the hot rocks into your container of water. Be careful not to drop them from a height as this can cause splashing of hot water.
  5. The water should start to boil after a few moments. Let it boil for at least one minute to ensure that it’s safe to drink.

Remember, this method only works for killing biological contaminants like bacteria and viruses. It will not remove any chemical pollutants.

5. Solar Disinfection

Solar disinfection, also known as SODIS, is a free and efficient method to purify water, especially in emergency situations. The method uses sunlight to destroy various bacteria, viruses, and parasites that cause diseases. Ultraviolet light (UV light) from the sun damages the DNA and RNA of these microorganisms, rendering them harmless.

Steps to use sunlight to disinfect water

Here’s how you can use solar disinfection to purify water:

  1. First, collect clear water in a transparent plastic bottle. If the water is cloudy, you should filter it first.
  2. Fill the plastic bottle up to three-quarters full.
  3. Shake the bottle for about 20 seconds to oxygenate the water. This step enhances the effect of solar radiation.
  4. Then fill the bottle to the brim and tighten the cap.
  5. Place the bottle on a reflective surface, like a metal sheet, and expose it to full sunlight for at least six hours. If the sky is cloudy, expose it for two consecutive days.

Please note that this method might not be effective against all types of microorganisms, particularly some types of parasites. Also, it does not remove chemical pollutants from the water.

6. Water Treatment Tablets

Potable Aqua Water Purification Tablets with PA Plus, Portable and Effective Solution for Camping, Hiking, Emergencies, Natural Disasters and International Travel, Two 50ct Bottles

Water treatment tablets are an easy and lightweight solution for purifying water in the great outdoors. They typically contain either iodine or chlorine dioxide, which can kill bacteria, viruses, and some types of parasites. However, they’re not as effective against more resistant organisms like Cryptosporidium and Giardia parasites, unless used correctly according to the manufacturer’s instructions.

Steps to properly use water treatment tablets

Here’s how to use water treatment tablets for purifying water:

  1. First, fill your container with the clearest, cleanest water you can find. If the water is cloudy, you may need to filter it first.
  2. Add the correct number of tablets based on the volume of water and the instructions on the package. Typically, it’s one tablet per liter of water.
  3. Stir the water to dissolve the tablet completely, then wait for at least 30 minutes. In colder water, you may need to wait up to four hours to ensure effective disinfection.

Remember that using water treatment tablets does not remove physical impurities or chemical contaminants from the water. Also, iodine tablets are NOT recommended for pregnant women, people with thyroid problems, those with known hypersensitivity to iodine, or for continuous use for more than a few weeks at a time.

7. Portable Water Filters

LifeStraw Personal Water Filter for Hiking, Camping, Travel, and Emergency Preparedness, 1 Pack, Blue

Portable water filters are a popular choice among hikers, campers, and survivalists due to their convenience and effectiveness. These devices function by physically removing pathogens and other impurities from the water through a variety of methods, including ceramic, fibre, and carbon filters. Some models also incorporate a disinfection stage to kill any microorganisms that may pass through the filter.

There are several types of portable water filters available on the market, each suited to different needs:

  • Pump Filters: These filters require you to manually pump water through a cartridge that removes bacteria, protozoa, and sometimes viruses.
  • Gravity Filters: They function by filling a bag with contaminated water and suspending it over a pristine container. The water passes through a filter due to the gravitational force.

By Anita Brown

Anita Brown is our go-to contributor to our emergency preparedness website. Anita brings a wealth of personal experience and professional expertise to the table, having weathered several awful natural disasters. Anita is currently working towards obtaining her Community Emergency Response Team (CERT) certification.