How to Get Safe Drinking Water When Travelling

We’ve been travelling and working on the road full time since 2010, and clean drinking water is one of those things you stop taking for granted pretty quickly. Over the years Jess and I have carried a Grayl UltraPress across East Africa, drunk straight from back-country streams through a LifeStraw on hikes like Havasu Falls in Arizona, and boiled more kettles of dodgy-looking tap water than I care to count. Here’s how we actually go about getting safe water wherever we end up.

There are really only three things to sort out.

First, find out whether the tap water where you’re going is safe to drink. If it is, you don’t need to treat anything, so just carry a reusable bottle and fill up. If it isn’t, you’ve got five reliable ways to make water safe: boiling, chemical tablets or drops, a filter, a purifier, or a UV light device. The distinction that matters most is filter versus purifier.

A standard filter removes bacteria and protozoa but not viruses. A purifier also removes viruses, which is what you want across much of the developing world. And if you already know you want a device and just need to pick one, we’ve compared our favourites in our guide to the best water filters for travel.

 

Why safe drinking water matters when you travel

Water is very good at carrying things that aren’t good for us: bacteria, viruses, parasites, and sometimes chemicals and heavy metals. The WHO and UNICEF estimate that around 2.1 billion people, roughly one in four of us, still lack safely managed drinking water at home (their 2024 figure). Contaminated water is linked to cholera, dysentery, hepatitis A, typhoid, giardiasis and more.

For travellers, the most common problem by far is travellers’ diarrhoea, which affects a large share of people visiting places where the water isn’t reliably safe. The cause is usually viruses, bacteria or protozoa in water or food.

It isn’t only about what you drink, either. The same water you’d treat before drinking can catch you out as ice in a cold drink, on a toothbrush, or on salad and fruit rinsed under the tap. It only takes a little contaminated water to ruin a week of your trip.

 

Is the tap water safe where you’re going?

For most of North America, Western Europe, Japan, Australia and New Zealand, tap water is generally safe to drink. Across much of Asia, the Middle East, Africa and Latin America, it generally isn’t, at least not for visitors. That single question decides whether you need to pack anything at all, so it’s the first thing to nail down.

Here’s how we go about it before a trip:

1. Start with an official source. The CDC’s destination pages, your own government’s travel advice and local health authorities are the reliable places to look, and this map gives you a quick global overview.
2. Next, work out what the actual risk is. Bacteria and protozoa are a concern almost everywhere, while viruses are mainly a risk where human waste can reach the water supply, which is most of the developing world. What’s in the water decides which method you need.
3. From there, let the risk pick the method. A hostel with a stovetop suits boiling, a multi-day hike suits a filter, and developing-world tap water suits a purifier (more on choosing below).
4. Finally, pack your method along with a light backup. A strip of chemical tablets weighs almost nothing and covers you if your main method fails.

As a rough regional guide:

Region	Tap water for visitors	Good to know
North America (US, Canada)	Generally safe	Some rural wells and older systems are exceptions
Western and Northern Europe	Generally safe	Taste varies by area, but it’s safe to drink
Japan, South Korea	Generally safe
Australia, New Zealand	Generally safe
Southern and Eastern Europe	Usually safe, but variable	Check locally in rural areas and older towns
Latin America (Mexico, Central and South America)	Treat or use sealed bottled	Some cities, like parts of Chile and Costa Rica, have safe tap water
Most of Asia (except Japan and South Korea) and the Middle East	Not safe for visitors	Treat, or stick to sealed bottled water
Most of Africa	Not safe for visitors	Treat, or stick to sealed bottled water
Many island nations	Variable	Check locally before you drink

These are rules of thumb, not a map. Tap safety varies within countries, it changes over time, and even where locals drink the water happily your stomach may disagree with the unfamiliar microbes. Always check the current CDC advice for your specific destination, and ask locally when you get there.

If the tap water is safe, you’re done! You don’t need any treatment, so just bring a reusable water bottle and refill it, rather than paying for and getting through single-use plastic.

 

Filter or purifier? The difference that matters most

A water filter removes bacteria and protozoa but not viruses. A water purifier also removes viruses. Everything else about choosing your kit is detail; this is the decision that keeps you well.

This is really about pore size. A standard travel filter has pores of around 0.1 to 0.2 microns, which is fine enough to trap bacteria and protozoa such as Giardia and Cryptosporidium, but viruses are far smaller and slip straight through. To catch viruses, which are far smaller, you need a much finer barrier, with pores down around 0.01 microns, or a different approach entirely such as chemical treatment or UV. The CDC’s water disinfection guidance sets out which methods handle what. Devices that clear this bar are sold as purifiers.

So a filter is perfect for a hike in the Rockies, where viruses aren’t the concern, but it isn’t enough for tap water in East Africa. If you’ll be somewhere viruses are a real risk, you want a purifier, a UV device, or chlorine dioxide. This is the concept; for which specific devices are filters and which are purifiers, and which we’d buy, see our guide to the best water filters for travel.

 

The five ways to treat water, compared

There are five methods to know about, and each kills a different set of things at a different speed.

One caveat first. We’re travellers, not doctors or water engineers, and drinking badly treated water can make you seriously ill. Treat this as a practical starting point from our own trips, check the current CDC or local advice for your destination, and get medical guidance if you’re unsure.

Method	Viruses	Bacteria	Protozoa (incl. Cryptosporidium)	Chemicals & metals	Time to safe water	Best for
Boiling	Yes	Yes	Yes	No	1 minute rolling boil (3 minutes above 2,000m), plus cooling	Anywhere with a heat source: hostels, apartments, camping
Chlorine dioxide (tablets or drops)	Yes	Yes	Yes, but up to 4 hours for Cryptosporidium	No	15 to 30 minutes; up to 4 hours for Cryptosporidium	A lightweight all-rounder and the best chemical backup
Iodine (tablets or drops)	Yes	Yes	No	No	About 30 minutes	Short trips only; not for pregnancy, thyroid conditions or iodine allergy
Chlorine / NaDCC (tablets)	Yes	Yes	Giardia yes, Cryptosporidium no	No	About 30 minutes	A light backup where Cryptosporidium isn’t the main worry
Microfilter (LifeStraw, Sawyer style)	No	Yes	Yes	Some, with a carbon stage	Immediate, filter as you drink or pump	Back-country US and Europe, where viruses aren’t the concern
Purifier (virus-rated, Grayl style)	Yes	Yes	Yes	Some, with a carbon stage	Immediate to a few minutes	Developing-world tap water, where viruses are a risk
UV light (SteriPen style)	Yes	Yes	Yes	No	1 to 3 minutes per litre	Clear tap water, where you have power or batteries

The column to watch is Cryptosporidium. It’s a chlorine-resistant protozoan, so ordinary chlorine and iodine tablets don’t reliably kill it, and it’s the reason the chemical rows above split the way they do. Boiling, chlorine dioxide, UV and a good filter all deal with it; iodine and standard chlorine tablets don’t. The CDC has a helpful comparison chart covering the same ground, and a fuller guide to water disinfection.

 

Boiling

Boiling is the most reliable way to kill pathogens, and it’s the CDC’s first recommendation wherever you can do it. It kills viruses, bacteria and protozoa, and there’s very little chance of getting it wrong.

Bring the water to a rolling boil for one minute at sea level, or three minutes above about 2,000m, then let it cool. That’s it. What boiling won’t do is remove chemicals, heavy metals, sediment or a bad taste, so it’s a disinfection method, not a clean-up-dirty-water method.

The practical snag is that you need a heat source and a vessel, and you need to hold a rolling boil for long enough. Most electric kettles switch off the moment they reach boiling point, which isn’t long enough to be sure, so they’re not ideal on their own. Some electric kettles do have a dedicated purification setting that holds the boil for three minutes. A stovetop kettle sidesteps the problem entirely, because you decide when it comes off the heat. Boiling works brilliantly in a hostel kitchen, an apartment rental or on a camping trip where you already carry a stove. It’s much less practical for a day of sightseeing, when you won’t want to lug a burner around, and you have to factor in cooling time before you can drink.

 

Chemical tablets and drops

Chemical treatment is the lightest and cheapest way to make water safe, which makes it the best backup to carry. You add a tablet or a few drops, wait, and drink. But not all the chemistries kill the same things, so it helps to know which is which.

Chlorine dioxide is the one to reach for. It kills bacteria, viruses and, given enough time, Cryptosporidium, which the others can’t manage. Bacteria and viruses clear in 15 to 30 minutes; crypto needs up to four hours of contact time. It also adds the least taste and is the safest of the three for longer use. Aquamira drops and Katadyn Micropur MP1 tablets both use it.

Iodine kills bacteria and viruses but does not reliably kill Cryptosporidium. It gives the water a noticeable taste (many kits include a neutralising tablet to help), and it comes with real health limits: it’s only for short-term use, up to a few weeks, and it shouldn’t be used by pregnant women, anyone with an unstable thyroid condition, or anyone with an iodine allergy. Potable Aqua is the best-known brand here, and one point often gets muddled: their classic germicidal tablets are iodine, and they sell a separate chlorine dioxide product too, so check which one you’re actually buying, because they don’t kill the same things.

Chlorine and NaDCC tablets, such as Aquatabs (MSR sell the same chemistry rebadged), clear bacteria, viruses and Giardia in about 30 minutes, but like iodine they don’t reliably kill Cryptosporidium, because it’s chlorine-resistant.

Whichever you choose, the same two rules apply. Chemicals don’t work well in cloudy water, so filter or pre-strain it first, and read the manufacturer’s instructions for the doses and contact times. A pack of these lives in our first-aid kit on every trip, even when we’re mainly relying on something else.

 

Water filters

A water filter removes bacteria and protozoa, including Giardia and Cryptosporidium, but it will not remove viruses. Many also include a carbon stage that pulls out some chemicals and improves the taste, and unlike chemicals or UV they work on cloudy water and give you clean water instantly.

That makes a filter a great choice for back-country hiking in the US, Canada or Western Europe, where viruses aren’t the main risk. Popular travel filters like the LifeStraw Go, the Sawyer Bottle and the Katadyn BeFree are bottle-and-filter systems you drink through. We’ve used a LifeStraw Go for years on hikes where there’s no treated tap water, including the multi-day trek down to Havasu Falls.

 

Water purifiers

A water purifier does everything a filter does and also removes viruses, thanks to a much finer mesh or an extra treatment stage. That makes it the safest single device for travel almost anywhere in the world, including places where the tap water carries a virus risk.

Because the mesh is finer, purifiers are usually a touch slower than filters and take a bit more effort to push the water through, but they’re still quite quick, treating roughly half a litre to three litres a minute. The Grayl UltraPress, which works like a French press, is the one we carry; other pump-style purifiers exist too.

 

UV light

UV devices kill bacteria, viruses and protozoa, including Cryptosporidium, by scrambling their DNA so they can’t reproduce or harm you. They’re light, quick, treating a litre in a minute or two, and simple to use.

The two catches are clarity and power. UV only works in clear water, because cloudy water shields the microbes from the light, so you’ll need to pre-filter anything murky. And it runs on batteries, which fade in the cold and can leave you stuck. UV is at its best for treating clear tap water in places where you’re unsure of the supply. The main brand is SteriPen, now owned by Katadyn; you’ll find UV devices in our filter guide alongside the filters and purifiers.

 

What about bottled water?

Factory-sealed bottled water is generally safe, and in some situations it’s simply the only realistic option, for instance where there’s no water source at all, or where the water is contaminated with chemicals or metals that ordinary treatment can’t remove. That last case is exactly when the CDC recommends sticking to sealed bottled water, and it’s the reason we always keep some as a fallback.

Two things to watch. Check that the seal is fully intact, because refilling used bottles and faking the seal with a dab of glue is a known scam in some places, and a carbonated bottle is a useful tell since the fizz is hard to counterfeit. The downsides are the cost, which adds up fast over a long trip, and the plastic: most of it isn’t recycled and ends up in landfill or the ocean. That’s exactly why we treat our own water wherever we can.

 

How to choose the right method for your trip

The right method is the one that matches the water you’ll actually face. A few questions sort it out quickly:

• What’s in the water? Where viruses are a risk (most developing-world destinations), you need a purifier, UV, chlorine dioxide or boiling. For back-country US or European hiking, a filter is plenty.
• Is the water clear or cloudy? UV and chemicals struggle with cloudy or dirty water. For murky sources, boil or filter, or filter first and then treat, which is a solid belt-and-braces approach.
• How cold will it get? Water left inside a filter can freeze and crack it, and batteries fade in the cold. Check the temperature rating if you’re heading somewhere freezing.
• How much water, how fast? Chemicals are light but slow, with a 30-minute to four-hour wait. Filters and purifiers give you water on demand. Boiling scales with the size of your pot.

For a good standard to look for on any filter or purifier, check whether it meets the NSF P231 protocol, a tough test for microbiological water purifiers, and whether the maker can show an independent lab report to prove it. Some products also meet EPA guidelines for microbiological purifiers. Whatever you buy, choose a maker that publishes its test results.

 

What we’ve learned treating water on the road

The biggest lesson we’ve learned is that a filter and a purifier are not interchangeable, and assuming otherwise is the classic mistake. Our LifeStraw Go had served us well on hikes in the US, so when we started planning a long trip across East Africa, the instinct was to just pack that. Then we did the reading, and remembered our 0.2-micron filter does nothing about viruses, which were a real concern where we were going.

That’s why we switched to the Grayl UltraPress for East Africa. Most of our water there came from taps, so it looked clear enough, but we had no idea what it was carrying, and a purifier that handled viruses as well as everything else was the only thing that let us stop buying bottled water and relax about it. It’s a slightly slower press than a straw filter, but for peace of mind across a couple of months of travel, that was an easy trade.

The other habit we’ve stuck to is never relying on a single point of failure. Batteries die, bulbs break, and filters clog at the worst possible moment, of course. Whatever our main method is, a strip of chlorine dioxide tablets goes in the bag as backup, because they weigh nothing and last for years. If you take one thing from all this, let it be that: pick the method that matches your destination’s real risk, and carry a light backup for when it lets you down.

 

Where to buy a travel water filter or purifier

This guide is about the methods and the choice between them. For the devices themselves, the specific filters, purifiers and UV units we rate, how they compare on capacity, weight and price, and which we’d buy for which kind of trip, we keep all of that in one place: our guide to the best water filters for travel. Sort out your method here, then head there to pick the kit.

 

Useful resources

We’ve linked to trusted sources throughout this guide. Here are the most useful ones gathered in one place, plus a few extras worth a read:

• The WHO’s drinking water fact sheet, for the global picture on water access.
• The CDC’s food and water safety page, a great starting point for travellers, its comparison chart of treatment options, and its water disinfection guide.
• Check the water safety for your destination on the CDC’s destination pages, and browse the wider CDC drinking water resources.
• For travellers’ diarrhoea, the UK’s TravelHealthPro fact sheet and this JAMA literature review.

 

Frequently asked questions

 

Is it safe to drink tap water when travelling?

It depends entirely on where you’re going, and it’s the first thing to check. Across North America, Western Europe, Japan, Australia and New Zealand, tap water is generally safe to drink.

Across much of Asia, the Middle East, Africa and Latin America, it generally isn’t safe for visitors. Check the CDC’s destination pages and local advice before you travel, and when in doubt, treat the water or drink sealed bottled water.

 

What’s the difference between a water filter and a water purifier?

A filter removes bacteria and protozoa, including Giardia and Cryptosporidium, but it doesn’t remove viruses. A purifier does the same job and also removes viruses.

That difference matters because viruses are a real risk in much of the developing world. A filter that’s perfect for a hike in Colorado may not be enough for tap water in East Africa.

 

Do I need a purifier that removes viruses?

You need one if you’ll be drinking water where human waste can reach the supply, which covers most low- and middle-income destinations. For back-country hiking in the US, Canada or Western Europe, viruses are rarely the concern and a standard filter is usually fine.

If you want one device that covers you everywhere, choose a purifier.

 

Does boiling water make it safe to drink?

Yes. Boiling kills viruses, bacteria and protozoa, and it’s the CDC’s first recommendation wherever you can do it. Bring the water to a rolling boil for one minute, or three minutes above about 2,000m, then let it cool.

Boiling won’t remove chemicals, heavy metals or a bad taste, but for killing the things that make you ill, it works every time.

 

How long do water purification tablets take to work?

Most tablets need about 30 minutes, though it varies with the chemistry and what you’re trying to kill. Chlorine dioxide clears bacteria and viruses in 15 to 30 minutes but needs up to four hours to deal with Cryptosporidium.

That waiting time is the main downside of tablets, so plan ahead and treat your water before you’re thirsty.

 

Do purification tablets kill Cryptosporidium?

Only chlorine dioxide tablets reliably kill Cryptosporidium, and even those need up to four hours of contact time. Iodine and ordinary chlorine or NaDCC tablets, like Aquatabs, don’t reliably kill it, because Cryptosporidium is resistant to those chemicals.

If crypto is a concern, use chlorine dioxide, boil the water, use UV, or pre-filter it with a good microfilter.

 

Are iodine water purification tablets safe for everyone?

No. Iodine is fine for short-term use for most people, but it shouldn’t be used by pregnant women, anyone with an unstable thyroid condition, or anyone with an iodine allergy. It’s also not meant for long-term use, so limit it to a few weeks.

If any of that applies to you, use chlorine dioxide tablets instead.

 

Is bottled water safe when travelling?

Factory-sealed bottled water is generally safe, and in some places it’s the most practical option. Check that the seal is fully intact, since refilled bottles with faked seals are a known scam, and a carbonated bottle is a good sign because the fizz is hard to fake.

The downsides are the cost and the plastic waste, which is why we treat our own water wherever we can.

 

Can a travel filter make seawater drinkable?

No. Travel filters and purifiers remove pathogens, but they don’t remove salt, so they can’t turn seawater into drinking water. They also won’t remove fuel, toxic chemicals or radioactive contamination.

In those situations, sealed bottled water is the only safe option.

 

Does UV light purification actually work?

Yes, in clear water. A UV device scrambles the DNA of viruses, bacteria and protozoa, including Cryptosporidium, so they can’t make you ill. The limitation is that it only works in clear water, because cloudy water shields the microbes from the light, and it needs power or batteries.

Pre-filter cloudy water first, and carry a backup in case the batteries or bulb fail.

 

What’s the best backup water treatment method?

Chemical tablets, specifically chlorine dioxide ones. They’re light, cheap, last for years, and work on their own or alongside a filter.

We always pack a strip of tablets even when we’re relying on a purifier, because a single point of failure isn’t something you want with your drinking water. They belong in every hiker’s and traveller’s kit.

 

What water treatment do you actually travel with?

For most trips we carry a LifeStraw or a Grayl, depending on the virus risk, plus a pack of chlorine dioxide tablets as a backup. In the US back-country we use a LifeStraw Go, which is a filter.

For places where viruses are a real concern, like our travels across East Africa, we switch to the Grayl UltraPress, which is a purifier. We’ve written up the full comparison in our guide to the best water filters for travel.

 

Further reading

That’s how we get safe drinking water on the road. Before you go, here’s some more of our content you might find useful:

• Our guide to the best water filters for travel, with our tested device picks.
• If you brew your own coffee on the road, we travel with an AeroPress, and we’ve reviewed our favourite portable coffee makers.
• Our packing list for Havasu Falls and our guide to the Havasu Falls hike, where we put our LifeStraw to work.
• A guide to doing laundry when travelling, and our picks for the best travel shoes for men and the best travel shoes for women.
• How to get online when you travel, including the best mobile hotspots and the best travel routers.

As always, we’d love to hear your thoughts, comments and questions on this guide! Just pop them in the comments below and we’ll get back to you as soon as we can.