Running out of water on a hike is more common than you might think. Don't panic — there are solutions for obtaining safe drinking water. But how do you actually purify water? Boil it? Treat it with UV rays? Use chemical purifiers? Use filters? Each of these solutions for purifying water while hiking has its own advantages and disadvantages, which you can find detailed below.
How to purify water while hiking: boiling water
It's one of the oldest methods in the book: boiling water to kill the micro-organisms and bacteria it contains. The method is straightforward and requires no specialist equipment. Simply build a fire and bring the water to the boil. If you need to cook at the same time, you can kill two birds with one stone. However, it's worth knowing that boiled water tastes flat. Beyond the taste, it's also worth noting that the water will be hot — not ideal if you're looking to cool down, unless you're willing to wait for it to cool.
It's also worth remembering that the boiling point of water depends on the altitude at which you find yourself. If you're going hiking in a location close to sea level, you can let the water boil for one minute — that's sufficient to kill bacteria, as water boils at 100°C at this altitude. The higher you climb, the lower the temperature at which water boils. But at these lower temperatures, bacteria are not killed immediately; they require a longer boiling time. At 4,500 metres altitude, water boils at 85°C. To purify the water, you'll need to keep it boiling for several minutes to eliminate all micro-organisms. If you're climbing Everest, water will reach boiling point at just 70°C, meaning you'll need to keep it at a rolling boil for at least half an hour.
How to purify water while hiking: UV purification
Today, highly advanced technologies exist for purifying water. Portable UV lamps are proof of this. The size of a pen, these lamps are both highly effective and practical. Simply switch on the device and move it in all directions through a container full of water — job done. To purify one litre of water, just one to two minutes of treatment is enough. The biggest advantage of this water purification technique is that the device is fast, compact and very lightweight. Almost all pathogenic organisms present in the water are eliminated during the process.
However, the organisms are not actually killed — they are simply rendered unable to reproduce. This is precisely why UV-treated water should not be left in direct sunlight for too long; if it is, reactivation of the organisms is possible. The main drawback of UV purification is that the treatment is ineffective against chemical pollutants. Furthermore, portable UV lamps are not within everyone's reach, as the technology remains very costly.
How to purify water while hiking: all types of filters
Filters can also be used to purify water. The principle is simple: water is passed through fine-pore filters. Particles and micro-organisms are retained, and the resulting water is clean and safe to drink. Several types of filter are available: cartridge filters, fibreglass filters, membrane filters, ceramic filters, and so on. Generally, filter treatment is quick. However, treatment time also varies depending on pore size — the smaller the pores, the longer the treatment. That said, it is a highly effective method: almost all bacteria and micro-organisms are captured by the filters. After treatment, the water can be drunk straight away — an ideal solution when you need to cool down. Filters do, however, require rigorous maintenance. The treatment works by retaining micro-organisms within the filter itself; if it is not cleaned regularly, it can become clogged and allow biological contaminants to develop.
The drawback of filter treatment is that it rarely eliminates all viruses. For all viruses to be removed from the water, the pores need to be very small. Alternatively, filter treatment must be combined with chemical treatment.
How to purify water while hiking: purification tablets
There is also a chemical process for purifying water. It involves placing a purification tablet in a given quantity of water and waiting for it to take effect. The advantages are numerous: tablets are a compact and cost-effective solution. However, it is worth noting that they do not kill all micro-organisms. Furthermore, you need to wait a certain amount of time for the water to be purified. Typically, this waiting time is between 30 minutes and 2 hours, depending on the brand of tablet.
