How to access clean and safe drinking water on backcountry hikes

When we planned our trip to Socotra, we knew drinking water would be one of our biggest challenges. With no potable tap water and a well-documented plastic waste issue on the island, relying on single-use bottled water was out of the question. Normally, wherever we can’t drink the tap water, we’d boil it and let it cool overnight to (re)fill our Klean Kanteen water bottle. But on a multi-day hike in a remote area in the Tropics, that’s not a feasible option, is it?

So, what did we do? We got ourselves a light-weight, on-the-go water treatment kit – which sounds easier than it was (but I guess that’s exactly the reason why you’re here). I did a ton of research before assembling our kit, and I share all my learnings (in layman’s terms) in this buyer’s guide.

What could be lurking in your drinking water?

If you’ve ever scooped up water from a river, mountain stream or even a seemingly pristine lake, you might assume it’s safe to drink. But natural water sources – even those that look clear – can contain a mix of contaminants, including:

• Bacteria (for example, E.coli, Salmonella)
• Parasites/Protozoa (for example, Giardia, Cryptosporidium)
• Viruses (for example, Hepatitis A, Norovirus)
• Microplastics
• Heavy Metals (for example, lead) and Chemicals (for example, pesticides)
• Turbidity (caused by sediments, organic matter and microorganisms).

Whether you’re planning a multi-day trek or want to stay safe while travelling in places where tap water isn’t drinkable, choosing the right water treatment solution is a key decision that could impact the outcome of your trip.

What water treatments exist?

Many travellers (us too, initially) assume that using a filter means any water source is safe to drink, but that’s not always the case. While filtration may remove contaminants, purification neutralises harmful microorganisms. Both have their place when making water safe to drink and understanding the difference can prevent serious health issues on the road. So, let’s dive into each in a bit more detail.

Water filtration removes contaminants

Water filters physically trap harmful substances, but their effectiveness depends on the filter type. Standard filtration methods include:

• Membrane Filters remove bacteria, parasites, and microplastics (but not viruses, chemicals, or heavy metals) by forcing water through microscopic pores. The lower the micron (µm) number, the more effective the filter—more on that below.
• Activated Carbon Filters remove chemicals and heavy metals as they attach to the highly porous and ginormous surface area of the carbon material. While they improve the taste of your water, they do not eliminate bacteria, parasites, or viruses.
• Electro-adsorption filters: These filters use an electrical charge to capture bacteria, parasites, microplastics, chemicals, and heavy metals. While some also claim virus removal, independent tests show they are not consistently effective.

Water purification neutralises microorganisms

Purification methods kill or deactivate microorganisms by affecting their DNA. Standard water purification methods include:

• Heat: Boiling water for at least one minute (3 minutes above 6,500 feet/2,000 metres) kills bacteria, parasites and viruses.
• UV-C Light: Short-wave UV light damages the DNA in bacteria, parasites, and viruses. It is a fast method but only effective in clear water.
• Chemical Disinfectants: These kill bacteria and viruses but need 10-30 minutes (sometimes even more) to be effective.

Still confused? Don’t worry. Here is a nice (high-level) chart of the different water treatment methods created by the Centers for Disease Control and Prevention (CDC):

How to make sure there are no nasties in your drinking water?

With water filtration (and some water purification methods) alone ineffective in removing all contaminants that could be present in your drinking water, combining filtration and purification provides the highest level of protection. You could use

• a ready-made all-in-one water treatment device (for example, the RapidPure Purifier+ Multi-Use POD System) or
• a membrane filter (to remove most contaminants) is used, and then boil or treat your water with disinfectant or UV-C light.

Whichever one you choose, if you want to remove cryptosporidium, your membrane filter must be rated 0.1µm (or lower).

What should you look for when buying a water treatment device/system?

As mentioned, the type and µm of your water filter of choice determine how effective it is when removing nasties. The efficiency of water filtration devices against (biological) contaminants is measured against guidelines issued by the US Environmental Protection Agency (EPA). To be considered adequate, your device needs to have the following (independently assessed) ratings:

• Parasites/Protozoa – minimum 3 logs (99.9%) – though if filtering water from stagnant water holes, you’d want to have 6+ logs;
• Viruses – minimum 4 logs (99.99%);
• Bacteria – minimum 6 logs (99.9999%).

I always thought the digits after the dot don’t matter (it all rounds up to 100%, right?). Yeah, Nah. Regarding water quality, every single number after the dot counts. This video by GearSkeptic opened my eyes (nerd alert).

How do water treatment solutions compare?

Below, we break down the most popular lightweight water filtration and purification options on the market, comparing key elements, including effectiveness, weight/dimensions and sustainability considerations, to help you decide the right one for your needs.

Bottles with Inbuilt Filtration

These allow you to drink straight from the bottle, filtering contaminants as the water passes through. They are great for solo travellers on hikes with reliably frequent water sources.

Bottom line With its electro-adsorptive filtration, the Pure Clear Pure Explore performs above systems that use hollow fibre membrane filters. While WaterToGo claims to do a similarly good job, 99.97% efficiency against viruses does not meet the EPA guideline of 99.99%—independent test results are published on the WaterToGo website.

Inline Filtration (Gravity and Squeeze) Systems

Inline filtration connects dirty and clean water carriers, filtering water through gravity (or by squeezing it through the filter). These are useful when treating more significant quantities of water at once and great for multiple people on multi-day hikes where the frequency and quality of water sources are uncertain.

Bottom line The standout here is the RapidPure Purifier+ Multi-Use POD System, which achieves higher efficiency through a combination of mechanical filtration and adsorption. On the flip side, however, it only treats up to 75 gallons/284 litres (until the filter needs to be replaced). Two of only a few 0.1µm filters on the market, the Sawyer Micro Squeeze and the HydroBlu Versa Flow, effectively last a lifetime (if regularly backwashed). More on that below.

Water Purification Options

Water filtration removes bacteria and parasites, but not all filters eliminate viruses. Likewise, heat, UV-C light and chemical disinfectants do not remove debris; thus, use your water filtration system first.

All chemical disinfectants leave a taste of the chemical used. While LifeSystems states in their marketing material that Chlorine Dioxide is tasteless, we found that it still has a chlorine taste. Taste neutralisers are available (or you can create your own by dropping a clean slice of lemon into your filtered and treated water).

Bottom line When it comes to water purification, the Katadyn Steripen Ultralight is in a class of its own. While expensive upfront, the cost per litre treated over its lifetime is actually much cheaper than any disinfectant drops or tablets. Of the chemical disinfectants, the LifeSystems Chlorine Water Purification Tablets are fast-acting and have the longest shelf life – a good option if you struggle with the Steripen’s upfront cost.

What water treatment kit do we use (and why)?

How to keep your water treatment kit in good shape?

Water treatment devices are not cheap, but you can keep your kit in top condition by doing a few simple things:

• Let your kit air out: After each use, we shake out any remaining water, dry all components, and store them in a breathable pouch. Avoid storing your system in a plastic zip-lock bag, as moisture gets trapped inside, creating the perfect environment for mould and bacteria to thrive.
• Backwash regularly: Over time, you will notice the flow rate of your filter reducing. So, whenever we have access to clean water, we backwash our filter – by attaching our clean water carrier (filled with clean water) to the clean side of the filter and squeezing water backwards through the filter until all the gunk is flushed out.
• Deep clean after every trip: We thoroughly clean our water carriers regularly, using dish soap, vinegar, or bicarbonate soda. This removes any lingering contaminants, mineral buildup, or biofilm. After washing, we air-dry all components before packing them into their storage bag/breathable pouch.

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