Bicycles are fantastic at getting us out there on the path less traveled, whether that means remote backcountry trails or roads through foreign lands.
But many of these places don’t have sinks or drinking fountains dispensing fresh clean water every few miles. And as humans, we have this pesky need: we need to drink water pretty often, or we die.
Thus it’s no surprise that the question of water purification for bicycle travel is a common one. Can you drink the tap water in countries where the locals do? What about water from backcountry streams and lakes? How about that slimy green water in the cattle trough over there?
There’s no one-size-fits-all answer, unfortunately, because it depends on where you are and what kind of bicycle trip you’re on. The best water filter for bikepacking in the US might be different from the best water purifier for bicycle touring in Nepal. But that’s all part of the fun, isn’t it?
I’ve logged plenty of saddle time in a wide range of places, from populated areas of the United States to emerging nations around the globe. In this post I’ll share everything I’ve learned about how to find or make safe drinking water when bikepacking or cycle touring.
If you’re in a hurry and just looking for my recommendation on the best water filter for bikepacking or touring, skip to the very end where I explain my favorite setup for any type of trip.
Otherwise, if you want to understand more about how to safely choose the right water sources and treatment methods in different circumstances, let’s start with some background.
Nasty Waterborne Pathogens
First, let’s quickly review our high school biology so we understand the types of nasty little buggers we’re trying to protect ourselves from.
E. Coli, Salmonella, Cholera
Size: 0.2 – 5 microns
Removed by most filters
Killed by chemical treatments
Common in natural water sources in developed countries
Size: 1 – 15 microns
Removed by filters
Not killed by all chemical treatments
Common in natural water sources in developed countries
Hepatitis A, Norovirus, Polio
Size: 0.02 – 0.3 microns
Not removed by most filters
Killed by chemical treatments
Uncommon in natural water sources in developed countries, except places with high human waste contamination
By far the most common problem caused by all of these: diarrhea and other digestive upset. Not usually some mild 24 hour bug… Think weeks of uncontrollable digestive problems.
In the case of viruses, a few rare cases can be dangerous or even fatal (Polio is still a problem in some developing parts of the world), though having the correct immunizations will help protect you.
Most of these contaminants make their way into water through the poop of infected people or animals. I know, gross. So it follows that water in areas close to animal pastures, or places where human waste is not properly disposed of, will have higher contamination levels.
Purifiers versus filters: Which do you need?
Simply put, purification methods handle all three types of nasty buggers (bacteria, parasites, and viruses). Filtration methods only handle two types; they don’t handle viruses, which are small enough to slip through.
Do you need a purifier, or just a filter? It depends on where you’ll be riding. At the risk of oversimplifying, here are three cases:
- For bicycle touring or bikepacking in developing parts of the world with questionable water and sanitation infrastructure, you’ll want to purify all your drinking water, whether it comes from the tap or from natural sources. These places tend to have higher risk of virus contamination, so a filter alone is not sufficient. For more detail, see this guide to water purification for travelers.
- For backcountry bikepacking trips in developed parts of the world where tap water is safe to drink, you should filter any drinking water from natural backcountry sources like rivers or lakes. Viruses are typically not a risk in the backcountry, so a purifier is unnecessary, though it won’t hurt to use one. For more detail, see this guide to backcountry water treatment. It’s intended for hikers, but also applies to bikepackers and anyone venturing into remote areas.
- For “front country” bicycle touring or bikepacking in populated areas in developed parts of the world, you should consider purifying water you drink from natural sources. While viruses are usually not a big risk in developed areas, outbreaks have been known to happen. Lakes or rivers in populated areas or busy recreation sites do carry some risk. So do cattle troughs and natural sources used by grazing animals.
Water Treatment Methods for Bicycle Travelers
There are a ton of water filtration and purification devices on the market these days. Choosing between them can be overwhelming, especially if you don’t already have a lot of experience with travel and/or backpacking.
Some of them are great, and some are pretty impractical for bicycle travel. Here I’ll go over some of the common methods, as well as a few less common ones, along with their pros and cons.
Gravity Filters (or Purifiers)
A gravity-powered system is easy to use: simply fill one bladder with dirty water, position it above an empty bladder, and let gravity do the work. They’re amazing for groups because they can treat large amounts of water efficiently, but a smaller capacity setup can work nicely for a solo cyclist as well.
They are most often available as gravity filters for backcountry use in developed countries, though gravity purifiers are available too. The purifiers add an extra component, usually chemical treatment, to deactivate the viruses that are small enough to slip through the filter’s pores.
Some filters in the squeeze and inline category (see below) can be set up as gravity filters too, with the right attachments.
Squeeze and Inline Filters (or Purifiers)
These filters use similar technology as gravity filters, but different energy to do the work. Instead of gravity pushing the water through, you’ll squeeze it through by hand or suck it through as you drink. Inline filters, in particular, are convenient because you don’t need to wait for the water to filter before you can hit the trail or road.
Pump Filters (or Purifiers)
Pump filters (and pump purifiers) were more commonly used before gravity filters became robust and affordable. My first backcountry water treatment method was a pump filter, and I appreciated it for the balanced workout I got during my hiking trips: pumping all that water would make my upper body as tired as my legs!
These days they tend to be bigger, heavier, and more work than their gravity/squeeze/inline counterparts, and I don’t see them used as often.
Chlorine Dioxide Drops or Tablets
Chlorine dioxide is a lightweight and versatile water treatment method for bike touring and bikepacking, but it needs to be used carefully. It’s effective against bacteria and viruses within 30 minutes, but the hard-shelled parasite Cryptosporidium takes 4 hours to inactivate.
This means that in areas with higher chance of contamination from people or animals, you need to carry (or leave sitting overnight) water treated with chlorine dioxide for 4 hours before you can safely drink it. In areas with less chance of contamination, typically remote high elevation mountain areas, you might consider risking a shorter wait period.
In my experience, chlorine dioxide is ideal as:
- Minimalist water treatment for fast-and-light trips in remote low-risk backcountry areas.
- A lightweight backup method to a filter or purifier.
- Used in combination with a filter and a 30 minute waiting period, they provide full purification. The filter removes the Cryptosporidium that the chlorine dioxide takes 4 hours to kill, and the chlorine dioxide kills viruses that the filter doesn’t catch.
Chlorine or Iodine
I list these chemical treatments separately from chlorine dioxide because there is a crucial difference: these don’t kill Cryptosporidium at all, not even after 4 hours. They also tend to have a more objectionable taste. For these reasons, if I’m going to use a chemical treatment method it will always be chlorine dioxide.
UV treatment devices like the SteriPen are effective purification methods, but have some drawbacks from a bicycle touring perspective:
- In cloudy or silty water, they neither remove the unappetizing particles nor zap the dangerous pathogens as effectively.
- They’re awkward for treating large amounts of water or using a hydration bladder.
- Though I’m sure they’re built to be robust, they are electronic devices and it’s possible they could fail or break.
Straw and Bottle Filters (or Purifiers)
These two methods aren’t very practical for cycle touring or bikepacking, unless you have a specialized use case.
Unless they can also be set up as a gravity or inline filter, straw filters only allow you to drink when you’re physically at the water source (not so great for carrying water with you). Better to get a gravity/squeeze/inline system that can also be used as a straw.
Bottle filters might work will for a quick day ride, but aren’t a practical way of carrying large amounts of water, and really limit the ways you can carry water on your bike, which is already a complex enough puzzle.
Best Water Treatment Method for Bikepacking and Cycle Touring
As bicycle travelers, our highest priority needs are:
- Treating water from many types of sources. Unlike hikers who usually drink from clean-ish backcountry sources, we drink water from all kinds of weird places. We need a system that is convenient to use when drinking from a clear mountain lake, a cattle trough in the middle of the desert, and the tap in that dodgy motel room in Cambodia.
- Treating large amounts of water at once. It’s not uncommon to carry 4 liters or more when cycle touring in hot climates, and we do it day after day after day. So we need treatment methods that don’t a) run out quickly, and b) take a long time.
- Carrying treated water in a variety of containers: hydration pack bladders, frame-mounted bottles, that XL Gatorade bottle you saved from the gas station, sometimes all of the above. Systems that only treat a small amount of water in a specific container (filter bottles, UV treatment, inline filters) can be inconvenient.
- Small and lightweight, to a point. Carrying stuff on a bike is a little easier than carrying it on our backs, so cyclists may not demand an ultra-minimalist setup the way a lightweight backpacker might. Still, no one wants to lug around extra weight if they don’t need no.
Putting these priorities together, here’s how I rank water treatment methods for bikepacking and bike touring:
Good Water Treatment Methods for Bike Touring and Bikepacking
- Gravity filter or purifier with at least 2 liters capacity, or a squeeze filter set up as a gravity filter (they’re basically the same thing).
- Chlorine dioxide drops or tablets: versatile, small, and light. They work well in combination with a filtration method (creating a purification method effective against all pathogens), or as a backup in case of filter failure. They require advance planning and/or two separate water containers, because they take up to 4 hours to work (30 minutes if Cryptosporidium isn’t a risk).
Bad Water Treatment Methods for Bike Touring and Bikepacking
- Pump: it’s hard to recommend pump filters/purifiers these days when gravity filters are so much easier and lighter.
- Straw: not practical for carrying water with you between sources.
- UV: not ideal for treating large amounts, doesn’t work in cloudy water, which is common if you drink from natural sources.
- Filter bottle: not a flexible way to carry water on your bike. Better to be able to use mix of hydration bladders and bottles properly sized for your bottle cages.
My Favorite Water Treatment System for Bike Touring and Bikepacking
After 10,000 miles of long-distance biking on 5 different continents, If I had to choose one water treatment system flexible enough to meet the needs of most bicycle trips anywhere in the world, here it is:
- Sawyer gravity/squeeze filter
- CNOC filter bag
- Chlorine dioxide drops (optional, used in certain circumstances)
How it works:
- Filter alone can be used with relatively clean sources in developed countries, and is especially convenient for a longer or more leisurely trip, or when sharing gear with riding partners.
- Chlorine dioxide can be used alone for a short / fast-and-light / solo trip anywhere in the world, or as a backup in case something happens to your filter.
- Both can be used together for full purification in higher risk developing areas. Filter the water, then add the chlorine dioxide and wait 30 minutes. You don’t need to wait the full 4 hours required for chlorine dioxide to deactivate Cryptosporidium though, because it gets removed by the filter.
My Picks For Best Water Filter / Purifier
These are the specific products I use, and how I use them.
Sawyer Mini Squeeze Filter
If filtering into a bottle, I hang the bag + filter from my handlebars and place the bottle beneath the filter nozzle. If filtering into my hydration bladder, I balance the bag + filter somewhere elevated, remove the bite valve from my bladder hose, and attach the end of the hose directly to the filter nozzle. Another option is to just filter into a bottle and then empty the bottle into the hydration bladder.
- For a long trip or trip with silty water, you will definitely need to bring the included syringe or another method for backflushing, otherwise the filter will clog and stop working.
- The filter can be destroyed by hard impact or freezing temperatures. Pack it somewhere safe and sleep with it on cold nights.
- The filter lasts a long time, but not forever. Keep an eye on usage if you’re on a very long trip.
Since the Mini came out, Sawyer has also released a dual-threaded version that looks like an improvement. I haven’t tried it, but I think it would screw directly on to a hydration bladder, which would make it even easier to fill (no need to remove bite valve to filter directly into the bladder). I’ve also read good things about the Sawyer Micro, the smallest and lightest new option, so you might want to check that out too.
I also want to give an honorable mention to the Platypus 4 liter gravity filter system. While not as compact as the Sawyer, it’s perfect for a couple or group touring together, especially if saving space is not a top concern.
CNOC Filter Bag
Pretty much the only thing about the Sawyer Squeeze that isn’t awesome are those horrible bags it comes with. They’re inflexible, they can crack or bust at the seams, they’re almost impossible to fill up from a shallow water source, and they can’t be used for a gravity-powered setup.
There’s an easy fix, and one of the best kept secrets in outdoor gear if you ask me: this CNOC hydration bladder from Amazon. The wide end makes it easy to fill up from almost any source, and the narrow end screws directly onto the Sawyer filter. Tie some paracord to the wide end and you have a gravity filter that you can hang on your handlebars or a tree branch and filter water while you eat your lunch, no squeezing required.
Aquamira Chlorine Dioxide Purification Drops
I usually prefer Aquamira drops to tablets because I carry water in all kinds of weird quantities. If I want to treat 2.5 liters of water in my hydration bladder, I can count out the exact number of drops (7 drops per liter, so I would use 18 in this case) instead of wasting half a tablet (1 tablet per liter).
The only time I prefer tablets is when they are solely an emergency backup on a shorter trip. In that case it’s smaller and lighter to pack just a few tablets than the entire bottle of drops (even though the drops are pretty darn small and light too).
Carrying Water on Your Bike
Once we’ve treated water, how are we going to carry it on the bike? I cover all the options in more detail in this post, but I’ll share a few thoughts here. For carrying on water on multiday bike trips, I look for these qualities:
- Multiple different containers; if one breaks or leaks, I want a backup. It’s also nice to sometimes put electrolyte or juice powder in one container and still have another for pure water.
- At least one container I can drink from while riding. A hydration bladder in my frame bag is perfect for this. Bottles are harder.
- At least one container I can easily take off the bike and use for drinking and washing at camp. A bottle is perfect for this.
- In hot or dry areas, the ability to carry up to 6 liters at a time to accommodate dry camping.
Here’s my favorite system:
- 3 liter Platypus bladder with hydration hose, which lives in my frame bag.
- Frame bag to carry the hydration bladder. Frame bags originated in the bikepacking world, but even if you are touring with panniers I highly recommend adding one to your setup. They use the frame triangle space far more efficiently than a couple of bottle cages, and they are in the perfect location for packing heavy things (like water) with minimal impact on bike handling. They don’t need to cost a fortune either; I’ve been using this affordable Moosetreks frame bag for 5500+ miles.
- Two of these huge Nathan 1.5 liter bottles on my front fork, whenever more than 3 liter capacity is needed. The bottles are indestructible, easy to use (two options for opening, a small and a wide), and make handy backcountry foam rollers for tight muscles after a long day of riding. I tour with only rear panniers, but if you use front panniers you could put the bottles inside them if space allows, or strap to the top somehow.
- Two of these burly Blackburn Outpost bottle cages to hold the bottles. They also work for holding stuff sacks of gear if you don’t need extra water. I replaced the straps with these awesome Voile straps, a mainstay of bikepacking gear, and for good reason.
- If your front fork doesn’t have bolts for bottle cages, you can still make this work. I’ve been using these Zefal Gizmo mounts. They work great while on the fork, but I’ve had to drill/crack apart two of them to remove the bottle cages after a long trip. Here’s a list of alternatives, if you’re in the mood to experiment.
The setup above gives 6 liters of water capacity in bikepacking mode (no rack). When touring with a rear rack and panniers, I can add another 5 liters by filling the CNOC filter bag and an extra 3 liter hydration bladder, one in each pannier. Obviously you can also just buy a few 1.5 liter bottles of water and strap them wherever you can, but I try to avoid using disposable bottles where possible.
This setup got me across two days of Sahara desert in Sudan with 11 liters total.
Finally don’t forget, in a pinch you can always boil your water to purify it! This doesn’t remove the grit and leaves you with a bunch of hot water, but if you have the fuel for it, it’s effective against all the nasty buggers.
More Bikepacking and Bike Touring Resources
If you’re currently drooling over the next trail or road you plan to ride, you might also find these helpful:
- Bikepacking: a beginner’s guide
- What to pack in your long-distance bike repair kit
- Bike touring the rugged and beautiful Carretera Austral
Find even more guides and gear reviews on the bike travel resources page.
New! Browse bikepacking and touring blogs from all around the world at BikeSleepBike.
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