We all know that Mexican tap water isn’t purified to the degree that the American digestive system is used to. But if one were to spend a long time there, they couldn’t avoid Mexican tap water forever. You’ll eventually get some in your mouth when you shower, for example.
So is there a way to ease oneself into Mexican tap water?
Not really. Even the locals can get sick from the water. Its not like it is consistently bad in one single aspect. People often die from bad water in third world conditions.
Depends a lot on where you’re staying in Mexico.
I stayed in a lot of hotels in a lot of major Mexican cities and drank the local water there in hotels, restaurants, etc., without concern or consequences for years. OTOH, I wasn’t out in some random small village.
So I think the OP might want to consider Mexican (or Latin American in general) tap water as being on a spectrum of danger, with the horror stories reserved for the more primitive areas.
Yeah, this isn’t like in movies where the hero (or villain) builds up a tolerance to some poison.
There are many different “poisons” (bacteria, algae, amoebas, etc.) that can set up shop.
When I’ve stayed with Mexicans, they drank filtered water.
I am not a Mexican, but have travelled to a bunch of third world countries. I just drink the tap water.
I know there are risks, but it is good enough for the residents, it is good enough for me.
The exception was some parts of Indonesia, where even the poorest drank bottled water
I’m heading to Indonesia this summer, and I had already decided months ago that I was going to drink bottled water exclusively, but this sure solidifies my decision.
It is amazing! Avoid Jakarta, you are going to fly in there, but wow, industrial strength of consumer capitalism with scarce regard for the poor.
There are some really cool parts of Jakarta, but watch your mental safety, travel… well, any taxi, bus, rickshaw etc is going to be at best interesting.
Trains are really good, though crowded.
Do, if you can find one, have an avocado cappuccino. Yes, they exist, it is normal coffee based cappucino, just with avocado added. It sounds beyond bizarre, but try it.
The completely unheard of fruits - go find a mangosteen - are incredible. Jackfruit curry. Dukka. So much variety.
ETA, @CairoCarol has way more experience with Indonesia than I do
Oh. Go to to Flores. Just go. You will thank me later after you get over the shock of your aeroplane doing short final over an active volcano at Maumere.
Whilst there are plenty of nasty things you just can’t develop full immunity to, it’s also true that for some pathogens (including some that cause food poisoning), a certain dose is required before it becomes likely that you will fall ill. Below that dose, your immune system just clears it all up before it can get a foothold.
It is a statistical thing though - it’s not like there is some exact number of E.coli cells that everyone can safely consume without effect, and it’s not the same dose for everyone, but for people with a functioning immune system, it’s not that just ingesting one bacterium will make you sick; it requires a dose sufficient to overwhelm the body’s defensive processes.
And those defences do adapt, somewhat, to the kinds of things that are frequently attacking, so to an extent, people do become more immune to many of the local pathogens. Not all of them, and not completely, but somewhat.
Tourists in hot places, coming there from cooler places, will tend to feel a need to drink more water than the locals who are adapted to the climate, so that also doesn’t help.
I used to have a house in Italy which wasn’t on mains water - the water came from a well so wasn’t for drinking. You just get used to using bottled to brush your teeth, and the tiny amount you might consume in the shower isn’t enough to strike you down. But as someone up thread noted, there’s sure to be some kind of filtration system you could get installed. Or get drinking water delivered by truck to a cistern in the garden! Both things I’ve witnessed people do in rural Italy.
Yes, I’m super pumped up about it. So much so that I’m currently learning Indonesian.
Jakarta is not on the programme. I’ll be staying mostly in and around Yogyakarta, and then fly to Bali for a few days.
Actually I was planning to start a thread to prepare for the trip a couple of months before leaving, similar to the New York one.
Bahasa Indonesia is by far, the easiest language to learn that I have tried. Basic conversation in Bahasa is really easy. It took me a couple of days on my first trip there to start haggling in markets. Now years later, I can recall plenty.
I am pariculary fond of the plural “bebek bebek” which descibes in an onomatapeic manner the sounds ducks make. (A flock of ducks) You can find them in roadside restaurants. The singular is just “bebek” without the repeat
My second is “orang orang” for plural “people” closely linked to “orangutan”, “people of the forest.”
I loved Yogya. Super great city. And of course Prambanan and Borodudur (historic temples) nearby.
But also, as the “hippie center of Indonesia” so much fun
I think we are drifting well, well off topic now though
Everything @scudsucker says about Indonesia is correct, though I must once again remind people that while “taxi Indonesian” is indeed easy, the language does have far more sophisticated levels and it’s not like you can become truly fluent with little effort. (While it is technically correct that “orang-orang” is a word, the chances of anyone saying that particular term are remote.* Indonesian is a “high context” language, meaning that plurals rarely need to be “spelled out,” as it were.)
The language is easy at first because there is no gender, copula, conjugation, or tense. That right there probably eliminates a year of tedious memorization. But it’s “agglutinative,” which means it has a whole lot of affixes that make subtle and not-so-subtle changes to the meaning of words. Once you start dealing with that, it’s just as hard as any language. I believe Indonesian ranks as a 3 out of 5 in terms of “how hard is this language for a native English speaker to learn?” That makes it about average.
*When I was first studying Indonesian, my language teacher was a veterinarian. So we talked about animals a lot. I was telling her, in my halting Indonesian, that my cat had thrown up, but I wasn’t worried, because sometimes cats throw up for no particular reason. This produced, in my basic Indonesian, an awesome sentence:
Sometimes = kadang-kadang
Cat, plural = kucing-kucing (or so I thought)
Throw up = muntah
To show that a verb is being done idly/with no particular intent, you double it. So, a sort of random, unimportant barfing could be characterized as “muntah-muntah.”
And so I said:
Kadang-kadang kucing-kucing muntah-muntah.
I was quite pleased with myself, and very disappointed to be corrected: a native speaker would never say “kucing-kucing” because you don’t need to. Oh well.
ETA: and for Gawd’s sake, DON’T DRINK THE TAP WATER.
There is a thing called Mithridatism where you slowly ingest small quantities of some toxic substance to build up an immunity to it. It is named after Mithridates VI, who regularly consumed small amounts of poison to build up an immunity in case his enemies ever tried to poison him (his father was assassinated by poison, so the risk was real). According to legend, when Mithridates was about to be captured by his enemies (and certain to die a long, horrible death at their hands) he tried to poison himself but was unsuccessful and needed to have his bodyguard stab him with a sword instead.
It’s not just a movie thing. It does actually work. However, it works notably better with some substances than others. If you regularly ingest heavy metals, all you are going to end up with is heavy metal poisoning. You aren’t going to build up a tolerance. On the other hand, snake handlers regularly inject themselves with small amounts of snake venom and do build up a resistance to it over time.
I don’t know how well it works with something like Mexican tap water. Anecdotally, a guy I used to work with (he has since retired) used to take a small sip of whatever the local water was whenever he went someplace for work. He would get mildly sick that night, but afterwards he claimed he could drink the local water without issue. That’s just an anecdote though. I don’t have any sort of factual cite to back it up.
Poking around online, I found a site that claims you can build up a tolerance to local drinking water, but the amount of time required to do so varies quite a bit from person to person. The claim did not have any cites to back it up, though.
I suppose therefore that it’s possible that you could build up a tolerance to the local water, or you could spend your entire time abroad with a nasty case of the squirts. Probably not worth taking the risk (IMHO).
It’s particularly effective with iocane powder.
It helps if your Sicilian isn’t as smart as he thinks he is.
You also need to watch out for water in other forms. I once spent a week sailing in Baja with no problems at all because we drank bottled water and cheap beer. But we made the mistake of stopping at Rosarita Beach for breakfast on the way home, forgetting that Bloody Mary’s weren’t going to be using bottled water for their ice cubes.
Lesson learned.
Anecdote.
Nearly a dozen years ago, I spent about five months meandering around Central America.
For the first few weeks, I studiously avoided the local water – brushing my teeth with bottled, no salads, no ice, no fruit that I didn’t peel myself, etc. – the regular stuff.
Slowly, I began to eschew those rules and start trying to acclimate to the tap.
Near the end of month one – traveling from town to town every few days (ie, probably not sticking to one municipal water source for very long) – I would daily fill my Camelback bladder with tap and drink it through the day (it was bloody hot and humid almost everywhere I roamed).
Never an issue.
Would I have been okay anyway? Did I just get lucky and travel to relatively low-risk locations? Maybe. Dunno. There weren’t two of me 
But I also had a UV light ‘pen’ sterilizer that I used just once, in the hinterlands of the Guatemalan mountains, where the Mayan diaspora had been forced to live, when a local basically ‘wouldn’t let me’ drink the rain water they’d collected. I used the magic lightsaber just to make him happy.
Didn’t get sick from that either.
FWIW, when I travel internationally, I try to make a habit of basically eating as much yogurt as I can. Does that help? No idea. But I like yogurt, so …
One possibility is that you were consuming micro amounts of bacteria in those first weeks even when you were avoiding the local water. The local water would be used for things like washing eating surfaces and fruits, which may have left behind small amounts of bacteria. You may have been ingesting tiny amounts at first which helped your body adapt. Then when you went to drinking the local water directly, your body had already acclimated to whatever was in the water.