Guide to Clean Drinking Water on Treks

If we were to ask you, how would you keep yourself fit while on treks or for that matter in any wilderness situation, what would your answer be?

Food?, Water?, Sleep? Or Physical/Mental fitness? You might be right in  naming these things but if you have to pick one amongst them, then what it would be?


If you ask me, I would say clean drinking water is the most important thing to survive. Mind it, it is not because I am a doctor or something but because it is actually true and most of the people fall ill on treks due to consumption of contaminated water. For a fact, thousands of travellers fall ill due to traveller’s diarrhoea and land up spending their vacations in hotel/hospital room rather than out exploring the wild. What most travellers fail to understand is that it is important to consume clean
water which is not just clean on visible level but also at micro level. But the question here would be… how do we know if the water is clean or how to clean it using some simple methods/tricks?

Here are a few methods that can be used to purify water-

  1. Boiling Water
  2. “Bringing the water to 160°F for a duration of 30 minutes or 185°F for 5 minutes has the same effect as bringing it to a boil.” - The Wilderness Medical Society.


    Steps to clean water by boiling:

    • Filter or remove the large particles from the water.
    • Bring water to a boil for 1 minute (for elevations up to 6,500
      feet) or 3 minutes (for higher elevations).
    • Let the water cool.
    • Drink

    Pros-

    • Fuel efficient way

    Cons-

    • Not effective against chemical contaminants;
    • Needs to cool down before drinking

  1. Bleach

Steps to clean water by using Bleach:

  • Filter or remove the large particles from the water.
  • Add 16 drops of bleach per gallon of water (or 4 drops per litre).
  • Mix thoroughly.
  • Let the water stand for 30 minutes.
  • Make sure the water has a faint chlorine smell.
  • Drink.

  • Pros- 

    • Very practical method
    • No fuel consumption


    Cons-

    • Hold time of 30 min
    • At higher altitudes, lower temp reduces the effectiveness of such methods.

  1. Iodine

Steps to clean water by using Iodine:

  • Filter or remove the large particles from the water.
  • Add 5 to 10 drops of iodine per litre of water.
  • Let the water stand for at least 20 minutes.
  • Drink

  • Pros-

    • Iodine is a great wound disinfectant, water purifier, and is very shelf stable. Iodine is often found in emergency medical kits.

    Cons-

      • Iodine is sensitive to sunlight and should always be kept in a dark place and/or in a dark coloured bottle.
      • Also, avoid drinking iodine treated water if you are pregnant, allergic to iodine, have thyroid problems, are on lithium.


  1. Water Filter
  2. Steps to use water filter:

    • Put intake into the water source.
    • Pump or push water through the filter element.
    • Collect the filtered water.
    • Drink.

    • Pros-

      • Light and highly mobile.
      • Can be used in combination with the bleach technique mentioned.

      • Cons-

        • Viruses are too small to catch with these filters.
      Various portable water filter bottle are available in market for travellers to use. These water purifier bottles are handy and effectively remove pathogens.

      List and comparison of various portable water purifier bottles/ water filters available in market-

      • Straw filters-

        Pros-

        • Efficiently removes all sediment and debris.
        • Removes the particles that cause the water to taste and smell bad.
        • Efficiently removes bacteria, viruses, protozoa, parasites.

        Cons-

        • The holes in the membrane get clogged with debris, sediment, and bacteria over time, so you have to change them.
        • Not very efficient at removing dissolved contaminants like chlorine, heavy metals, and pharmaceuticals.
      • Pump filters-

        Pros-

        • Improves the water’s smell and taste.
        • Usually, an activated carbon filter has to be changed only once a year.
        • The beneficial minerals in the water are not eliminated by this filter.

        Cons-

        • The filter itself may become a breeding ground for the trapped bacteria if it’s not changed when it’s supposed to.
        • The pores in the carbon granules are large, and they won’t stop some bacteria species.
      • Bottle filters-

        Pros-

        • Effectively reduce the heavy metals, arsenic, and other dangerous contaminants in the water.
        • Effectively blocks the bacteria and viruses from reaching your drinking water.
        • Allows the beneficial minerals to remain in the water.

        Cons-

        • Dissolved salts like fluoride and nitrates are not reduced.
        • Does not reduce cadmium.

      • Gravity filters-

        Pros-

        • Efficiently removes bacteria, viruses, protozoa, and parasites from the water.
        • Can remove some herbicides, pesticides, and other man-made contaminants that may affect the water.
        • Can filter out chlorine from the water.
        • The filter cartridges can last for up to one year of use.

        Cons-

        • Larger than other types of water filters.
        • Is made out of multiple parts.
        • The first container can contaminate the second if it’s not stored properly.

      • UV filters-

        Pros-

        • Improve the water’s smell and taste.
        • Works quickly.
        • Beneficial minerals are not removed from the water.
        • Effective against bacteria, viruses, protozoa, and parasites.

        Cons-

        • Run on batteries.
        • Their effectiveness decreases as the water is dirtier.
        • The sediment and debris in the water can negatively influence the filter’s effect.
        • Does not affect heavy metals or chemicals like chlorine.

    List of few of the Best Portable Water Purifiers in India-

  3. Lifestraw Go Water Bottle
  4. Key Features:

    • Filters up to 1000 litres of water
    • Two stage filtration
    • Replaceable filter and carbon capsule, easily available online
    • Removes 99.99% of waterborne bacteria & protozoa
    • Reduces turbidity, filtering down to 0.2 microns
    • 100% chemical free
    • Made of high-quality food grade plastic as per US FDA standards
    • Capacity: 650ml

    • Eureka Forbes Aquaguard Personal Purifier Bottle
    • Key Features:

      • 100% chemical free
      • Filter life: filters up to 420 liters of water
      • Replaceable filter
      • Soft squeeze bottle with see-through water level indicator and dust cap
      • BPA free and non-toxic plastic bottle
      • Removes 99.9% bacteria & virus
      • Capacity: 700ml
      • Available in attractive colors and designs

    • Tata Swach InstaSip Instant Purifier Bottle
    • Key Features:

      • Filters up to 1000 litres of water
      • No chemicals used
      • Anti-microbial, food-grade soft squeeze bottle
      • Removes 99.99% of bacteria and 99.9% of protozoa
      • Bottle Capacity – 740 ml