Water purification: Essential tips for hiking

The pros and cons of water purification methods

Water is essential for survival, but how long a person can go without it varies widely depending on temperature, activity level, health, and access to shade. In hot or exposed conditions, dehydration can become life-threatening within a day, while in cooler environments survival may extend longer. Because untreated water can carry serious health risks, understanding reliable water purification methods is critical when hiking. Choosing the most appropriate method depends on your environment, equipment, and available time, and taking unnecessary risks with untreated water should always be avoided.

Boiling

Boiling is one of the most reliable ways to make water microbiologically safe. It effectively kills bacteria, viruses, and protozoa that can cause illness. In most situations, bringing water to a rolling boil for at least one minute is sufficient. At higher elevations, where water boils at a lower temperature, a longer boil time of around three minutes is recommended. Boiling does not remove chemical contaminants or heavy metals and requires fuel and time, which may be limiting factors in some situations.

Bleach

I’m not a big fan of ingesting chemicals, but you can use liquid household bleach, free of additives and scents, to disinfect your water. It should contain a hypochlorite solution of at least 5.25%. If the water is clear, add 2 drops of bleach per litre of water; add twice that amount (4 drops) per litre if the water is cloudy. After adding bleach, the water should be stirred and allowed to stand for at least 30 minutes before use.

Water purification tablets

Water purification tablets can be an effective option when used correctly and according to the manufacturer’s instructions. Different tablets use different active ingredients and require specific contact times to be effective. Always check the instructions on the packaging and be aware of expiration dates, as older tablets may be less effective. While tablets can treat many microorganisms, some types may not be effective against all parasites, and treated water may have an altered taste.

Water filters

This is my go-to solution when possible. Commercial filters are available in a variety of sizes, styles, and capabilities. One of my personal favorites is the Sawyer Mini Water Filter because it removes things that many others don’t, weighs only 57 grams, and will filter 378,540 litres of contaminated water. Katadyn manufactures an outstanding pump purifier, and MSR also produces a highly rated pump-style filter. During an extended emergency, though, it’s important to know how to improvise your own water filter; it’s surprisingly simple and requires a container, some cloth, sand, and charcoal. A quality filter is one of only two methods that can remove nearly everything from contaminated water.

UV water purifier

UV water purifiers can be effective when used correctly, but they have important limitations. They require batteries or charging, only work with clear water, and typically treat small volumes at a time. UV treatment inactivates many microorganisms but does not remove sediment or chemical contaminants. For these reasons, UV purifiers are best used as part of a broader water treatment strategy rather than relied on as a sole method in remote or emergency situations.

SODIS

Solar water disinfection, or SODIS, uses sunlight and clear PET plastic bottles to inactivate microorganisms in water. It can be effective under the right conditions, typically requiring several hours of strong sunlight and relatively clear water. SODIS does not remove chemical contaminants and is dependent on weather, daylight hours, and temperature. While it can be useful in some survival situations, it is slow and produces limited volumes of treated water.

Distillation

Without a doubt, the most effective means of purifying water is distillation, but it’s certainly not the most convenient. It requires staying in a fixed area, and a bit of ingenuity. You could use the same type of still used for making alcohol to quickly produce a substantial amount of pure water in a short time but that requires specific hardware and a fire which may give away your position. Another option is a solar still in certain environments under certain circumstances. The biggest upside of distillation is that it eliminates everything; bacteria, viruses, protozoans, heavy metals, and other chemicals.

Final word

Ensuring a safe and reliable water source is crucial when participating in outdoor adventures. The importance of understanding and employing proper water purification methods cannot be overstated, as water is essential for survival, and contaminated sources pose significant health risks. Each method, from boiling and bleach to water filters and distillation, comes with its own set of advantages and limitations. It’s crucial to weigh these factors carefully based on your specific circumstances, considering factors like fuel availability, portability, and the nature of the water sources you might encounter.

While some methods, like boiling and commercial filters, stand out for their reliability, others, such as UV purifiers and SODIS, present viable alternatives with certain limitations. Adapting to the situation and having a versatile approach to water purification can be crucial in the unpredictable and dynamic outdoor environment.

Remember, staying well-informed about the latest advancements, adhering to recommended guidelines, and regularly checking equipment for expiration dates are essential practices. Whether you’re a seasoned hiker or a novice adventurer, making informed choices about water purification methods ensures that the elixir of life remains a source of sustenance and not a potential threat during your outdoor pursuits. Stay prepared, stay hydrated, and enjoy the journey responsibly.