Pretty much whenever you move, the water will taste different. Maybe it'll be harder, maybe softer, maybe it'll have been purified with a different process or different chemicals. Chances are, you may not like it to start with, and may even have to get a different kind of tea (oh the horror!). However, this question isn't about that...

There's a fair bit of the world where locals can drink the water without issue, but visiting tourists are generally advised to drink bottled water to avoid Delhi Belly and the like.

If you find yourself moving to such a place, drinking bottled water might be fine at first, but is unlikely to work long term. At some point, you'll come across ice cubes made with local water, drinks made with local water, fruit or salad washed with local water, or something like that.

Knowing this, and knowing the initial risks of GI problems, how do you go about acclimatising to the local water in a situation like that?


7 Answers 7


You're going to have to accept that your body doesn't know how to deal with some of the local pathogens/bugs just yet, and will need time to get used to it. You don't want to overwhelm yourself, so you could start small - just brushing your teeth with water - small amounts to start 'infecting' yourself with the local stuff.

Although this so-called traveler's diarrhea usually resolves within three to five days (mean duration: 3.6 days), in about 20% of all cases it is severe enough to require bed-rest, and in 10% the illness duration exceeds one week (source - Wikipedia).

Where you are trying to adapt will vary in how long it takes to acclimatize to the local issues - one study in Nepal suggested seven years, while students in Mexico took just eight weeks (source - book).


Generally, you will adapt slowly, but probably you'll never get the same level of immunity as the locals, who are used to poor hygiene and contaminated water from the childhood.

The immune system of children is developing rapidly to adapt to the dangers from outside world. Notice how often children are ill... this is a painful process, and if you'd just like to start drinking contaminated water, you'll have to go through the same.

There are some things that strengthen your immune system: a lot of sleep, regular meals, low level of stress, moderate sport on free air. You should also expose yourself to the pathogens in small portions. Drinks made from local water is too extreme, fruits washed with local water sounds like a reasonable start, just eat one and wait a few days for reaction. If it's OK, you can increase the exposure.

But you must be aware, that infection with some kind of parasites may cause long-term or permanent health damage, so if the local water is thought to be infested with parasite eggs, it may be much wiser to treat using only bottled water and not eating any fruit or salads outside as a permanent solution.

  • 1
    It doesn't have to be poor hygiene or contaminated water, different bacteria may also cause problems.
    – PatomaS
    Mar 20, 2014 at 2:56
  • @PatomaS good water is expected to have no significant amount of bacteria (there are always bacteria, in every drop of air, so microbelessness is unreachable).
    – user41
    Mar 20, 2014 at 6:09
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    I don't understand your comment, where did you get the idea that I said something about "no bacteria"?. I said "different", as in not the same as you are used to.
    – PatomaS
    Mar 20, 2014 at 6:17

As others said, it might take a while to build up immunity to the critters in the water, even water that is technically safe to drink.

I used small square ice cubes, from a tray that makes 20 cubes instead of 10 or 12. You can probably find these in your grocery store or home center, they only need to be big enough to fit in your mouth to melt comfortably, and are fantastic for delivering yourself small measured doses of the local water over time.

Start with one a day for a week until any GI problems subside. Then go to two per day, then three, then to the point where you're having a soda with a bunch of local ice. Depending on where you are, this could take a few weeks to a few months or even longer - but you'll eventually bring your tolerance up in a more controlled way. You can just stick one or two in any drink and let it melt if you don't like the thought of taking ice like a mint.

Once you're able to be fine with a glass of (something) after 4 - 5 cubes have melted in it, you should be fine to have a glass of tap. I recommend filtering it, however, just because there is gross stuff in water all over the world. A Brita pitcher or similar is fine for this.

Remember, water quality can change - even just a few kilometers away, so you might be fine with tap water at home but get a bit of discomfort from water you had eating out. It's important to remember your consumption, both when and where.

It took me about a year before I finally stopped having issues in Metro Manila (though, after six months, problems became rare), and I can pretty much whet my whistle at any tap without a problem now.


In my experience, locals tend to distrust the water more than foreigners think. If you are concerned about pathogens in the water, keep in mind that many people in most countries I have been to boil tap water if they are going to drink it, even if the government advertises the drinking water as safe. As one individual in Quito, Ecuador told me, "I trust the government when they say the water is safe to drink. I don't trust my pipes." Quito water was considered safe to drink only recently and in my own trip there in, I think, 2010, my kids drank the water before we could advise them not to, with no ill effects.

So this is an area where the advice I would give actually runs counter to your question and that you should get local advice. If in doubt, boil the water first. If you are trying to build your immunity, start with small doses of the water, as a lot of things have to do with letting intestinal flora develop so they aren't overwhelmed by. Keep in mind that locals may boil water a lot more than you think.

A second point I would make is that water is only one way you can get sick. Approaches to food and food safety differ greatly around the world. I have gotten really sick from food far more often than sick from water, and not just from pathogens (spicy food tends to hit my stomach differently from different areas). Shocking your digestive system with a major change is a big part of the problem.

So get local advice on the water and boil it if in doubt (chances are, the advice will be to boil the water IME). And introduce yourself to local food and particularly fermented foods and drinks slowly (since these are usually microbially alive but often probiotic in smallish doses).

Also keep in mind that small quantities of water are far less likely to make you sick than larger quantities. If you are drinking bottled water, you may start by eating fruit washed in local water, then eat rice cooked with local water, then try to go more native.


I think that you can limit the exposure to the local water infections in one more way that is not mentioned in the other answers I think: You can purify reasonable amounts of water at home.

You need a chlorine desinfection, plastic bottles and a fridge. Just use the chlorine dosage mentioned on the bottle for drinking water / well water desinfection, and then put the water in your (better really clean) fridge, in bottles without lids. The water should be clorine-less after circa 6 hours.

Another option is to boil all the water and let it cool down in clean closed bottles outside the fridge. Such water should be stored for only short periods of time (no more than 1 day, depending mostly on local temperatures).

Using chlorine or boiling the water is in general significantly cheaper than buying bottled water, and gives you a good protection at home. There are even professional water cleaning systems, but I don't think it's reasonable to get one unless you really can't stand local water. Once you do this at home, you have a good level of protection, and you can get accustomed to the local water as explained in the other answers.


This might not be the answer that you're looking for, but I always just drink the water. Whether I've been in Colombia, Armenia or lots of other countries, I've never had a problem.

  • Are those places where tourist guidebooks suggest you don't drink the water? The places I've in mind for the question are ones where locals do drink the water, but visitors are suggested not to
    – Gagravarr
    Mar 17, 2014 at 15:19
  • @Gagravarr It depends. Wikitravel says this about Colombia "The water is drinkable right from the tap in most of the major cities, but be prepared to buy some bottles if you go to the countryside." I found that to be true. In the big cities I drank the water directly from the tap. In small villages in the countryside even the locals didn't drink the tap water. I really haven't been anywhere including a lot of developing countries where I couldn't drink the water. The one exception has been Ethiopia. Mar 17, 2014 at 15:33
  • WikiVoyage on Bangalore foreign tourists should be cautious about consuming water - Locals seemed happy drinking tap water in restaurants etc, but they all suggested I get bottled water at such times. I'd like to avoid having to do that forever!
    – Gagravarr
    Mar 17, 2014 at 15:39
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    @Gagravarr That is one of those things where I'd suggest you just start slowly. As I've said, I've never really had a problem. But try just drinking small amounts at first so that your system can get used to it is what I would do. Mar 17, 2014 at 15:53
  • Sorry, this is not a real answer to the question. It's similar to saying: I use to have unprotected sex with HIV+ people and I have never got infected.
    – yo'
    May 20, 2014 at 12:02

If you are going to live in a new place not just as a tourist, but for a long term, then I suppose there is no better way to develop immunity than to expose yourself to whatever new elements and their associated organisms that present themselves in the new environment.

I tend to think that even those people---like myself---who grew up in developing countries, where hygiene and sanitation are not the best, and live for a considerable period of time in a developed country, would still have to go through gastrointestinal problems when they go back to their home country for a short visit.

From personal experience, even between developed countries, the germs might be different, because the climate are not exactly the same, and you would likely contract a new kind of viral/bacterial infection in the first few months after moving to the new place (my family got diarrhea/vomiting a few days after moving from Norway to UK). But I guess that's how one gets his/her immune system adapted to the new conditions.

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