How to Filter Water in the Wild

Access to clean and safe drinking water is an absolute necessity when spending time outdoors hiking, camping, or in a survival situation. Consuming contaminated water from lakes, rivers, ponds or other untreated sources can result in a variety of waterborne illnesses that can rapidly incapacitate you and ruin any outdoor adventure. Familiarizing yourself with various methods for filtering and purifying water in the wild can help ensure you stay properly hydrated and avoid health issues.

This comprehensive guide covers different techniques, from boiling and chemical treatments to pump filters and DIY natural filtration, that allow you to filter sediment, bacteria, viruses and other contaminants from untreated natural water sources. Read on to learn how to easily make backcountry water safe to drink!

The Critical Importance of Water Filtration

Drinking water straight from natural sources without any form of filtration or purification should be avoided at all costs when in the wilderness. Here’s why:

• Animal and human waste – Faeces and waste from wildlife, livestock and people can introduce dangerous pathogens.
• Bacteria – Water may contain illness-causing bacteria like E. coli, Salmonella, Campylobacter, Shigella, etc.
• Viruses – Contaminants like norovirus, rotavirus, hepatitis A, etc can all lead to vomiting and diarrhea.
• Parasites – Giardia, Cryptosporidium, Cyclospora and others can infect the gut and intestinal tract.
• Agricultural runoff – Pesticides, fertilizers and other chemicals can pollute waterways.
• Protozoa – Unfiltered water may contain harmful protozoan cysts.

Drinking untreated water can lead to severe consequences:

• Intestinal sickness, nausea, vomiting, diarrhea
• Dehydration and electrolyte imbalance
• Hygiene issues
• Potentially life-threatening waterborne diseases

With so many hazards, proper water filtration is non-negotiable for outdoor adventurers and critical for survival.

Boiling Water

Boiling is one of the simplest, most effective methods of water purification. Here’s how it works:

i. Fill a pot, pan, kettle or metal container with water from a lake, stream, spring or other source.

ii. Heat the water until it reaches a full rolling boil. Once bubbling vigorously, boil for 1 minute or longer.

iii. Allow the water to cool before carefully transporting and storing it.

Boiling water kills virtually all disease-causing microorganisms including bacteria, viruses, parasites and protozoa by denaturing their proteins through heat.

Pros of boiling water:

• Extremely effective method that eliminates most contaminants
• Simple procedure requiring only a heat source and metal container
• Water cools quickly once removed from heat

Cons of boiling water:

• Does not remove sediments, salts or heavy metals
• Requires significant amount of fuel for heat source
• Not practical for filtering large volumes of water

While boiling is highly effective for purification, water may still have an unpleasant taste or appearance. Additional filtration can improve this.

Chemical Water Purification

Using chemical disinfectants is a popular method of water purification in the wilderness:

i. Purchase water purification tablets containing chlorine dioxide, iodine, or other chemicals from outdoor retailers.

ii. Add tablets to water containers or bottles according to dosage on packaging.

iii. Shake or stir water and tablets together, then wait the indicated contact time.

Chemical treatments eliminate bacteria, viruses, protozoa and other contaminants by disrupting their cellular proteins and disinfecting the water.

Benefits of chemical purification:

• Very effective against common pathogens
• Portable, lightweight tablets perfect for hiking and camping
• Fast acting compared to some methods

Drawbacks of chemical purification:

• Can leave unpleasant chlorine or iodine taste and odor
• Not effective against some cysts like Cryptosporidium
• Results can be impacted by cold water temperature

Note: Always check expiration dates before using tablets. Replace annually or as recommended.

Pump Water Filters

Pump water filters force suspect water through a specialized filter using hand pressure:

i. Select a pump filter designed to eliminate bacteria and protozoa. Popular models are the MSR Miniworks, Katadyn Hiker, or Platypus Gravityworks.

ii. Place intake end of filter into water source. Attach output hose if filter includes one.

iii. Pump the handle in a steady motion. Filtered water will flow out of output end.

iv. Clean filter regularly backflushing and scrubbing membranes. Replace filter cartridges per manufacturer.

Membrane filters physically trap particulates and pathogens in tiny pores while allowing purified water to pass through.

Advantages of pump water filters:

• Effectively remove bacteria, protozoa, microplastics, sediments and more
• Fast water flow rate compared to some methods
• Durable and long-lasting if properly cared for

Disadvantages of pump water filters:

• Repeated pumping can be tiring on hands and shoulders
• Higher cost than some alternatives
• May struggle with heavily sedimented water

Pump filters excel when portability and fast flow rates are needed. Bring cleaning supplies to maximize filter lifespan.

Gravity-Fed Water Filters

Gravity-fed water filters use gravity to pass water through a filtration medium without pumping:

i. Select a gravity filter like the Platypus GravityWorks, which hangs from a tree.

ii. Place dirty water into the top container and hang or position above the clean container.

iii. Gravity pulls the water through the filter into the lower bottle as purified water.

iv. Backflush and clean the filter element periodically as directed.

Gravity filters use a similar filtration medium as pump models but without manual pumping.

Pros of gravity-fed water filters:

• Lightweight, compact, and portable design
• No effort or pumping required
• Filters larger quantities at a time

Cons of gravity-fed water filters:

• Slower flow rate than pumps or other methods
• Filter housing is fragile and may crack if frozen
• Not ideal for solo use with just one container

Gravity systems shine when filtering water for groups. Position the system and let physics do the work!

Straw-Style Personal Water Filters

Straw filters allow drawing water through a filter membrane directly as you drink from a water source:

i. Obtain a straw-style filter like the LifeStraw, Sawyer Mini, or similar model.

ii. Place the intake end into suspect water source.

iii. Simply sip clean water through the output end as the integrated filter purifies.

Super-portable and convenient, straws use hollow fibre membranes that remove bacteria, protozoa and most parasites while sipping.

Benefits of straw-style water filters:

• Ultra compact and lightweight for portability
• Filters water effectively on demand as you drink
• Simple to use with no setup required

Limitations of straw-style water filters:

• Not suitable for filtering larger quantities of water
• Require careful maintenance to avoid clogs
• Limited filter lifespan depending on model

Straw filters excel as a personal use, emergency, or minimalist water filtration solution.

DIY Water Filtration Methods

In survival scenarios without filters, it’s possible to DIY natural water filters using found materials:

i. Dig a hole and line it with grass, sand and charcoal to create a natural filter.

ii. Collect pebbles, gravel, sand, and charcoal in bottles or buckets with tiny holes poked in the bottom.

iii. Place fabric or cloth over end of water container to remove sediments and particles.

DIY filters made from natural components act to trap contaminants and purify through adsorption and mechanical filtration.

Advantages of DIY natural water filtration:

• Uses found natural materials requiring minimal tools
• Very affordable option in emergency scenarios
• Removes some Sediments, protozoa and larger pathogens

Drawbacks of DIY natural water filtration:

• Less effective on bacteria and viruses compared to commercial filters
• Takes more time and effort to construct and maintain
• Materials require frequent changing and replacing

DIY filters work well to remove sediments and parasites but should not be relied on as a primary purification method.

Choosing the Right Water Filtration System

When picking a water filtration strategy, consider:

• Group size and amount of water needed
• Length of trip and duration needed
• Environmental factors and water source
• Weight and portability limitations
• Budget and availability of materials

Ideally combine multiple purification techniques like pre-filtering via gravity or DIY then chemical or UV treatment for full protection. Remember to frequently service and replace filters and chemicals. Stay hydrated out there!