Is this water safe to drink?
Getting the answer to this question wrong can be disastrous on any hike or backpacking trip. Unless you are a camel or a cactus, you are going to need some clean water whilst hiking.
Dehydration is dangerous but drinking bad water can have some unpleasant side-effects. At best you could end up cutting your hike short and having to turn back.
On a thru-hike or multi-day trek it's not always practical to carry enough water so you may have to drink from rivers and streams.
Fortunately there are some great ways to make sure that only the cleanest water passes your lips. This involves both filtering out any potential nasties as well as sterilizing - or purifying - the water that you’re planning to drink.
Some products will either filter or sterilize and for the safest water you’re going to need two separate products. Or one product that does both.
Best Backpacking Water Filter Reviews
This water filter combines the excellent filtering that LifeStraw has become famous for with the convenience of a great hiking bottle.
The 0.2 micro first stage filter filters out bacteria and protozoa.
The second stage filter uses activated carbon to remove any odor, taste, chlorine or dissolved chemicals like pesticides that may be in the water.
The bottle has a wide mouth that allows for easy filling from a stream and a convenient mouthpiece incorporated into the lid.
Once the bottle is filled the water passes through the two filter stages and then through the mouthpiece.
Eventually the filters will need to be replaced. You’ll get around 100 liters before you need to replace the carbon filter and at least 1000 liters through it before you need to replace the first stage filter.
The first stage filter is essentially just a LifeStraw and it can be removed and used on its own.
What We Like
- No need for a separate filter and water bottle saving space and hassle
- First stage filter removes 99.9999% of bacteria and 99.9% of protozoan parasites
- Second stage activated carbon filter removes odor, chlorine, dissolved solids with zero aftertaste
- Durable construction
- Carabiner clip allows for easy attachment to pack
What We Don't Like
- Leaks a little when not upright
If you’re looking for a really small and cheap water filter then it’s tough to beat the Sawyer Mini filtration system.
It’s extremely light and filters out anything bigger than 0.1 micron. The flow rate is a little slow if you’re using it to refill your hiking bottle but it flows fast enough if you’re taking a sip through it.
It comes with a drinking pouch that you can squeeze to drive the water through the filter or you could use the straw it comes with to drink directly from a water source.
It will also connect inline with your hydration pack or screw onto a standard 28mm water bottle thread.
Sawyer claim it’ll give you up to 100,000 gallons of filtered water but you do need to backflush the filter every 5 to 10 gallons to unclog the filter.
What We Like
- Attaches inline to your hydration pack
- Screws onto most disposable bottles (28mm thread)
- Filters down to 0.1 micron so it'll remove even the smallest of silt particles
- Very light and compact not taking up space in your pack
- Filters 99.99999% of bacteria and 99.9999% of protozoa including giardia and cryptosporidium for those times when you just have to drink the dirty river water.
What We Don't Like
- Flow is a little on the slow side for impatient people like me
Some pump water filter solutions can be overly complex but the this water filter from MSR hits the sweet spot between function and simplicity.
It’s ideal for light to moderate use while backpacking or camping. The pump handle is simple to operate and with the 4 to 1 leverage it makes it easy to pump just over 1 liter per minute.
It has a 80 micron stainless steel prefilter and an activated carbon core which helps to get rid of any odor or taste the water might have. It has good quality silicone hoses that are color coded to prevent any contamination.
Cleaning in the field is easy. The water filter comes supplied with a cleaning brush and once you’re done you simply fold the handle away to pack it up compactly into the supplied stuff sack. We really liked that the water bottle adaptor fits a few different bottles including a wide mouth nalgene.
What We Like
- Removes 99.9999% bacteria and 99.9% protozoa
- Activated carbon core ensures fresh tasting, odor free water
- Lever action pump is simple to use and offers good flow rate
- Very lightweight - only weighs 11 ounces
- Decent cartridge life of 750 liters
What We Don't Like
- Not suited to supply more than 1 or 2 people with water
If you’re looking for the most hardcore water filter that removes a lot more than other commercial water filters then the Guardian is a great choice.
It’s built rock solid and was originally designed for military use. The pump handle is solidly constructed and delivers water a lot faster than other pump water filters. With a rate of 2.5 litres per minute this works just as well for personal use or for larger groups.
We really like that it doesn’t require any cleaning. With each pump stroke it goes through a self-cleaning cycle.
It has a nipple at the bottom to connect a hose for easy filling of a container or camelback as well as an adaptor that screws onto nalgene compatible bottles.
It filters down to 0.02 microns so it will filter out viruses. It comes at a high price tag but this offers significantly better filtering than the cheaper solutions. This is one of the best water filter units we’ve seen.
What We Like
- Military grade water filter removes protozoa, bacteria, particulate and even viruses
- Very fast flow rate - pumps 2.5 litres per minute
- Extremely rugged - withstands freezing and drops
- Pump is self cleaning - no backwashing required
What We Don't Like
- High Price Tag
- At 17.3oz it’s a little heavier than other pump filters
This is a compact, highly packable and easy to use water filter solution.
The kit includes 3 reusable water pouches (12oz, 16oz, 32oz), screw on filter, drinking spout and cleaning syringe.
The pouches are collapsable and roll up really small. The filter can be used with the pouches but also screws onto a standard water bottle.
The small mouth of the pouch does make it a little slow to fill unfortunately. It’s ideal for one or two people for fast and light trekking.
Fast fill hydration pack adapters are also available now so you can use the squeeze filter to refill your hydration bladder without having to remove it from your pack.
To backflush the filter you need to be sure to bring along the syringe. If you clean it regularly you may never have to replace the filter because they claim a life expectancy of 1 million gallons.
What We Like
- Filter screws directly onto water bottle
- Filters pretty quickly at 1 liter/minute
- Very easy to use
What We Don't Like
- The mouth of the pouch is a little small so it takes some time to fill
- To backwash the filter you need to remember to pack the supplied syringe
The SteriPen Adventurer is for serious hikers that want a lightweight, compact water purifier that is easy to use.
It uses UV to kill the microorganisms in the water so there’s none of the aftertaste, waiting time or allergy issues that you get from using iodine or chlorine.
You simply press the button once for 1 liter or twice for half a liter and then stir your water with the SteriPen. Once the light turns off your water is safe to drink.
It only takes around 90 seconds to purify a liter of water. The UV light kills the DNA of the microorganisms so they can’t reproduce once inside you.
This product is so effective that it’s the only water portable water treatment device to receive the Water Quality Association’s gold seal.
Because you need to stir the water it’s only practical to use with a wide mouth bottle.
What We Like
- Compact and lightweight so very little excuse to leave it at home
- Reusable for up to 8000 liters - that should keep even the thirstiest of us hydrated!
- Kills 99.9% of harmful microorganisms, including Giardia, Cryptosporidium, viruses, protozoa and bacteria
- Uses UV so there’s no aftertaste or allergies due to added chemicals
- Water sensor can be used as a flashlight
- No wait time - sterilizers a liter of water in 90 seconds
What We Don't Like
- Battery operated so you have to make sure your batteries are charged
- Has to be used with a wide mouth container
Whether you need to purify 1 liter of water for yourself or 20 liters for your hiking party this great water purifier has you covered.
It uses mixed oxidant technology to purify the water. You simply mix a brine solution made from any salt and any water and pour it into the little slot.
Once you select the volume of water you want to purify and start the reaction it uses electrolytic action to produce chlorine and other oxidants from the brine. Once the reaction is complete you pour the solution into the water and wait 30 minutes before it’s safe to drink.
There are two storage compartments in the device for salt but it’s a good idea to pack a little extra if you’re going to be out for a while.
The purifier can be charged either via the USB port or by using the built-in solar panel and a single charge is good for around 150 liters.
There are no replaceable parts and the only consumable you have is normal table salt so it’s really cheap to use.
The ability to scale between small and large quantities makes this great for a hike or even in your bugout bag.
What We Like
- Treats anywhere between 1 to 20 liters at a time - so great if you are car camping or going backpacking with a group
- Kills 99.9% of bacteria and viruses including Giardia and Cryptosporidium
- Charges via USB or built-in solar panel
- 60,000 liter lifetime with no replaceable parts
- No pre-filtering required
- No bad taste added to water
- Very durable and fits into the palm of your hand
What We Don't Like
- Takes 30 minutes to purify water
- High price tag
If you want a simple and cheap way to disinfect water then these iodine tablets are a good option. The tablets are really simple to use.
Simply add 2 tablets for every liter of water that you need to purify, shake the bottle up and then wait for 30 minutes.
Iodine tablets are very effective at killing microorganisms in water but usually leave you with water that has a brownish color and a horrible taste.
To remove the iodine taste and color simply drop 2 of the PA Plus tablets into the treated water and after 5 minutes you’ll have purified water without the horrible taste and color.
This is not a long term water purifying solution and should rather be used as your backup plan rather than your primary water purifying solution.
Also, if you have an iodine allergy then you’ll want to skip these.
Once you open the bottle the tablets in the bottle will only be good for 12 months but they’re cheap so buy a few bottles for your hiking and emergency kit.
What We Like
- Cheap and lightweight - easy to keep in your backpack for emergencies
- PA plus additive removes iodine taste and color that you normally get with these tablets
- Small bottles take up little space in pack
- Simple to use
- Very effective at killing viruses, bacteria and parasites
What We Don't Like
- Only really intended for short term or emergency use
- No good if you have an iodine allergy
- Takes 30 minutes to work
Another simple and cheap way to purify water on the go, these chlorine dioxide tablets are a worthwhile addition to your backpack.
Killing viruses and bacteria by the simple addition of a tablet to the water, these are a good alternative to iodine. Personally I hate the taste of chlorine, but I prefer that to a dose of Giardia.
It’s as simple as popping an individually packed tablet into one liter of water, waiting for 15 minutes - or 30 minutes if you are worried about Cryptosporidium.
They won't filter silt or other suspended particles, so step away from that murky river water full of hippo-poop!
I wouldn’t use these as my primary water sterilization method, but they make for a good backup, and are lightweight enough to keep in the bottom of your backpack.
What We Like
- Cheap, lightweight and easy to forget about in the bottom of your pack
- Great for emergency sterilization of water from suspect sources
- Effective at killing viruses, parasites and bacteria
- Doesn't taste as bad as a dose of Giardia
What We Don't Like
- Takes 30 minutes to work
- Won't filter the water at all, so best used with a clear water source
We love the SteriPen. It’s not a great solution for large volume water purification but for personal use on a hike it’s perfect.
I used the SteriPen on an Everest Base Camp trek and enjoyed being able to sterilize tap water in the various tea houses along the way. Certainly beats buying water in plastic bottles!
I love the no-fuss operation and the fact that there’s no 30 minute waiting time like a lot of other solutions.
I also really like the fact that this solution doesn’t involve adding any chemicals into the water.
We also really like the LifeStraw Go water filter bottle.
The convenience of having the filter built into the bottle is great.
The fact that it has both a standard filter and an activated carbon filter definitely puts it ahead of most other water filters.
This is my go-to water bottle for when I'm out on a day hike or traveling to parts of the world where the water is less sanitary.
For backpacking trips it works well, but if I was setting up base camp for the family, I'd go for a larger device.
Best for Budget
If you’re looking to save some money then the Sawyer Mini water filter is your best bet.
You get excellent filtration in a compact and cheap water filter. The only drawback is that it’s a little slow and needs backflushing every now and again.
I'd recommend this one if you go camping occasionally and don't want to spend the extra money.
Normally we wouldn’t touch the stuff because the color and taste of iodine or chlorine treated water is just horrible.
With the PA Plus tablets added you get safe drinking water that tastes and looks (relatively) good without having to spend a lot of money. The Katadyn is a good alternative if you don't want to use iodine.
Portable Water Sterilizer and Filter Buying Guide
Why Treat Water When Backpacking?
Sitting next to a stream of water while taking a break from your trail run or hike is a great way to relax. But don’t be fooled by how crystal clear that water looks.
Pretty much all surface water is contaminated with either bacteria, protozoa, viruses or all three. A study done in 1992 found that about 97% of the lakes and rivers in the USA were contaminated with either the protozoan parasites cryptosporidium or Giardia or both.
While that sounds pretty scary you’d probably be ok drinking from a lot of the streams you cross on your hike. But every time you do it’s basically a lottery. If you manage to ingest one of these bugs the rest of your backpacking experience is not going to be as much fun as you expected.
Better safe than sorry.
Backpacking Water Sources
Here are a few things to consider when choosing where to fill your bottle:
Before you can choose the best way to make your water safe it’s important to know what makes it dangerous.
In general the things you want to remove from the water are bacteria, protozoa (parasites), cysts, viruses, dissolved chemicals and particulate like sediment.
There are a number of potential water contaminants to look out for with the following being the main culprits:
What System Works on What Pathogen?
Water Filter vs. Water Sterilizer for Backpacking
A water filter will normally only remove things that are around 0.1 to 0.3 micron or larger depending on the filter. This is fine for removing bacteria, protozoa, cysts and particulate.
A filter will not remove viruses from water. Viruses are smaller than 0.1 micron and can only be killed by sterilizing with iodine, chlorine or UV light.
A good water sterilizer will kill bacteria and viruses but can’t remove dissolved chemicals from the water.
So should I get a water filter or a water purifier? If you want to be 100% safe you’re going to need both.
If you’re traveling in a developing country where sanitation isn’t always the best then packing both is worth the real estate it takes up in your pack.
If you’re backpacking through the countryside in the US and you’re far away from any potential sewage contamination then a filter should be all you need.
How Water Filters/Purifiers Work: An Overview
A water filter uses a membrane or tiny hollow tubes to block contaminants while allowing water to pass through. The size of the holes (pores) in the filter determine the smallest things it can filter.
Dirty water goes in the one side and clean water comes out the other. A filter will not be able to remove dissolved chemicals like heavy metals or salt from the water and the majority will also not be capable of removing viruses.
The filter needs to be periodically cleaned to keep it from becoming clogged and eventually will need replacing.
A water purifier doesn’t actually remove anything from the water but rather it kills any bacteria, parasites or viruses in the water.
If you scoop up some slightly muddy water from a pool and purify it you could drink it safely but it’s not going to taste great. Whatever bugs were in it will be killed but you will still have the particulate suspended in the water.
Your best approach is to filter the water to remove as much as possible and then to purify it to kill anything that made it past the filter.
Even with the best water filter and best water purifier you still won’t be removing heavy metals like chromium or lead so choose your water source carefully
Chemically Contaminated Water vs. Particulates
Standard water filters use very fine microfibers to trap particulate and bacteria.
They can’t remove dissolved chemicals, odors or bad tastes from the water. To remove these you’ll need a filter that uses an absorbent medium like charcoal, also sometimes referred to as activated carbon.
A filter that uses activated carbon will absorb chemicals like pesticides, herbicides and other Volatile Organic Chemicals (VOC), heavy metals, bad tastes and odors that would otherwise pass through a standard filter.
Is There a Difference Between Filtered & Purified Water?
Filtered water will look perfectly clean but that doesn’t mean that it’s safe to drink. It may still contain viruses.
Water that is purified may not always look the cleanest but whatever viruses or bugs are in it will be dead so it will be safe to drink.
Filtered water will usually taste better than water that is simply purified because the particulate will have been removed from it.
Water Sterilizing Methods
Water purification is typically done by either treating the water with UV light or adding chlorine or iodine to the water.
There are pros and cons for each of these methods.
Works really fast and there’s no need for long waiting times after treatment. With cloudy water it may be necessary to pre-filter the water to guarantee the inactivation of all microorganisms.
Water sterilization tablets are either made of Iodine or Chlorine.
Iodine is very effective at purifying water but leaves you with water that really doesn’t taste great. Some people have an iodine intolerance or allergy. If you take Lithium, if you have thyroid problems or if you’re allergic to shellfish then chances are that you’re allergic to Iodine.
Adding Chlorine to water is also very effective. You don’t have as big a taste issue but in both cases it takes around 30 minutes to purify the water.
My main issue with these is that I don't like the addition of chemicals to my water. And in order to get rid of the foul taste, you add further chemicals.
However, when given the choice between a filthy intestinal infection, or a few chemicals, I'm happy to purify my water with these tablets.
Regardless of purifying method you use, remember that they will not be able to remove dissolved chemicals from the water. They merely kill any bacteria in the water.
Types of Water Filter
These use a pouch, or water reservoir, with a filter at the bottom of the pouch. Water is scooped up into the pouch and then it is hung from a point higher than the bottle you need to fill. Gravity forces the water through the filter and down the pipe. These are the easiest and quickest water filters to use when supplying larger amounts of water to a group of people. The filter will remove bacteria and parasites but not viruses and you can usually put a charcoal cartridge inline with the filter to remove odors and taste. If you’re camping somewhere in the US then this is a solid choice. Your water source needs to be deep enough to scoop with the pouch so it doesn’t work well with shallow sources. If you’re looking to move fast and light then you may want to look at a more compact filter.
Basically a filter that screws onto a flexible water pouch. Once filled, you squeeze the pouch and it forces water through the filter. These are great for personal use for a quick drink while on a trail run. The water pouch collapses and stashes easily into your pocket. It’s a good option to fill your own bottle but too small and slow to supply a larger group. Also, there’s no charcoal in the filter so you’re stuck with the taste and smell of the water you scooped up.
Instead of using gravity this filter has a lever attached to it that pumps water through the filter when operated. Water is taken up through the inlet hose, it’s pumped through the filter, and exits through a hose on the outlet side. The handles can be a little fiddly to use sometimes and it takes a lot more elbow grease to get your water than a gravity filter does. The pros are that you can pump water up from a really shallow source and the filter takes up very little space in your pack. Most pump filters will only remove parasites and bacteria while the more expensive units like the MSR Guardian will filter out viruses too. Some of these filters also incorporate activated charcoal to remove odors and taste. As soon as something has moving parts there’s a chance something will break. Some of these filters have durability issues with the handles and o-rings.
Probably the most famous of these is the LifeStraw. It’s a plastic tube with a filter inside that you suck water through as you would with a regular straw. These are the ultimate in personal use, lightweight and compact water filters. They will remove bacteria and parasites but most won’t remove viruses. If you spend a little more for the LifeStraw Mission or Family 1.0 models then you’d be able to filter viruses as well. These are really easy to use but only really supply enough water for personal use. Cleaning is easily done by blowing instead of sucking so that excess water is backflushed through the filter. Eventually the filter gets clogged and it’s too difficult to suck water through it. After around 4,000 liters you’ll need to dispose of it and buy another as these don’t usually have serviceable parts.
Water Bottle Filters
If you already have your favorite water bottle but want to be sure the water is safe to drink then simply screw on one of these filters to the mouth of the bottle. Upend the bottle and gravity forces the water through the filter and into your mouth. These work well on the trail but the small amount of water they filter make them unsuitable for supplying your camp. The filter will remove parasites and bacteria but not viruses and the absence of carbon in the filter means you won’t be improving the taste of the water much.
Water Purification Methods
Boiling your water will kill all parasites, bacteria and any viruses as well. It doesn’t affect the taste of the water and it is very effective and cheap way to make it safe to drink. It’s a good option if you’re camping but not practical when backpacking or hiking. The amount of fuel and time you need boil the water makes this a very inefficient process. You’ll also need to wait for ages before the water is cool enough to drink.
Treating your water with chemicals like iodine, chlorine or oxidizing agents are all easy and effective ways to kill any bugs or viruses in the water. These chemicals can alter the taste of the water though. Iodine in particular gives the water a pretty unpleasant taste. Chlorine doesn’t affect the taste nearly as much but Giardia and Cryptosporidium can be Chlorine resistant so you will need to filter the water before purifying with Chlorine. It does take a little while for the chemicals to do their job so you’ll need to wait 15 to 30 minutes before drinking the water. Water treatment tablets are fairly cheap and take up very little space in your pack so they are a good option if you insist on packing super light.
Exposing water to UV light kills 99.99% of all harmful bad guys in water including bacteria, parasites (including Giardia and Cryptosporidium) and viruses. It uses no chemicals and doesn’t affect the taste of the water. It also works a lot quicker than chemical purifying. If the water has a lot of particulate in it then it does reduce the effectiveness of this method. There are some great compact UV light water purifiers that you switch on and just stir the water in your bottle for a minute or so. The drawback is that these work with batteries so make sure you’ve got a fresh pair in and a backup just in case. This is probably the best water purifying option for personal use but these devices can get a little pricey. The UV bulb will also eventually need to be replaced if you use it a lot.
Types of Water Filter
The kinds of filter media used in water filters are generally hollow fiber, ceramic, fiberglass, silica depth. Each of these have their respective pros and cons.
Excellent area-to-weight ratio means you get very effective filtering in a small, light package that’s good for around 1,500 to 2000 liters. The higher surface area also offers a higher flow rate than what other filters do. Hollow fibre filters are less durable than other types so you need to treat them carefully or make sure the housing is designed to protect the fibers when dropped. Replacement cartridges are expensive.
Offers excellent filtering, high flow rates and long lifespan of around 2000 litres. The drawbacks are that it is heavy and requires regular scrubbing to prevent it from becoming clogged. The ceramic filter wears down from cleaning and will eventually need to be replaced.
If the pore size is sufficiently small this type offers good filtration at a low price. It clogs easily though, is more fragile than ceramic and the flow rate isn’t as good either. Lifespan reduces significantly if used with silty or turbid water.
Offers excellent filtering at a good value price point. It offers a reasonable flow rate but not as good as you get from hollow fibre and ceramic. The lifespan of these filters runs to around 750 liters.
What is Micron Size for Water Filters?
When a water filter specification mentions “microns” it’s an indication of how effective the filter is at removing the bad stuff from the water. The figure quoted refers to the size of the pores in the filter and give you an idea of what the filter will stop and what it will let through. Bacteria range anywhere from 0.2 to 60 microns while viruses are around 0.005 to 0.3 microns [source]. The smaller the pores, the better it will filter but the lower the flow rate through the filter will be.
The Role of a Pre-filter (Do I Need One?)
The lifespan of your water filter is highly dependant on the amount of turbidity or silt in the water. If the water source you’re using is clear then there’s no need for a pre-filter. If the water looks murky or you can see that there’s a lot of sediment in it then it’s best to use a pre-filter. Simply pouring the water through a t-shirt or bandana will do a fairly good job of removing most of the sediment. Your water filter can then handle the rest. It will require less backwashing and will last a lot longer too.
Taking Care of your Water Filter
It doesn’t matter what type of water filter you buy, it will eventually need replacing. There are a few ways to make it last longer though.
Choosing the best water filter comes down to how much water you’re going to need and what water source you’re going to be using. For fast and light trekking small water filters like the LifeStraw or a squeeze filter are fine. If you’re catering for a bigger group then get a pump filter with a decent flow rate or a gravity filter.
If you’re hiking in the US, far away from any human settlements then a good microfilter that goes down to 0.2 microns should be all you need. Cryptosporidium and Giardia are the main things you’ll need to avoid. If you’re going to be near popular camp spots or traveling in developing countries you’ll want to either be sure that your filter removes viruses or be sure to purify the water after filtering it.
When you’re considering the cost of the filter be sure to consider the total cost of ownership and not just the initial purchase price. The lifespan of the filter cartridges and the cost to replace them can make a big difference to the overall cost.
Drinking bad water can ruin your hike far quicker than drinking no water will.
To cover all your bases it’s advised to have both the best portable water filter as well as the best portable water sterilizer in your kit. If you absolutely have to choose then go with a good two stage water filter.
You are more likely to encounter bacteria and parasites on a hike than viruses and filters are a lot easier to use when you’re on the move.
Just don’t get careless with the water outlet of the filter and make sure that the clean water side never comes into contact with suspect water.