Exactly. I should have written: Icing down beer that is in cans and bottles.
There are three types of bad water.
One is potable water that has a different mix than the water you are used to. This is what makes your average traveler mildly sick, and it can happen even in first world countries. It’s not a big deal. No tap water is sterile, and usually it’s just a period of adjustment.
Then is water contaminated with e coli, giardia, amoebas and what have you. This will make you sick-- sometimes violently, sometimes critically, and sometimes chronically. You really don’t want this to happen. Most things can eventually be cured, but the big gun medicines are very unpleasant, and even carcinogenic. We are talking more than a bellyache here. I once lost 10 pounds in a week due to giardiasis. It’s bad.
Most places make some effort to treat their tap water, so you won’t get sick every time. But if a pump breaks, or the shipment of chlorine is late, or the sanitation guy is home sick, or there is a lot of runoff from a rain storm- things go bad. So while you can drink a cup now and then, it’s playing Russian roulette. Sometimes you don’t have much choice, and some stay lucky for years. But it will probably eventually catch up with you.
To prevent this, you have four options. One is iodine, which you can’t do long term and tastes funny. It’s only a good option if you are wilderness traveling. Another is bleach, which works fine, but can taste funny and requires time for the bleach dissipate. Then there is boiling, which works but is expensive (fuel costs money) and a pain. A very good filter (not a Brita!) can work well and is easy, but isn’t perfect protection and is best combined with boiling.
You also need to use this in ice cubes and with your tooth brushing. Washing with it is okay, as long as you aren’t gulping and you let your dishes dry before using. Swimming in most places is a bad idea, but for other reasons (schistosomiasis). There are sometimes tricky situations, like vendors who inject water into melons to make them juicier. Be aware and cautious of street food. But don’t avoid it entirely, because it is awesome (and in reality, you have to be more cautious of restaurants aimed at tourists). Just focus on good that is steaming hot.
Raw fruits and veggies should be peeled soaked in bleach water for 40 minutes and then rinsed in purified water. Human waste is a common fertilizer. You’ll notice locals don’t tend to eat raw veggies.
Finally, there is heavy metal. This is not so much from pipes, but from industry polluting the water sources. Tourists really aren’t getting enough exposure to worry about it, but if you stay a year or more, you ought to take precautions, at least with your home drinking water. The only way around this is distilling your water. You can get home distillation machines. It’s a pain, but beats cancer.
In some countries there are trusted brands of bottled water. In others, you can’t trust that bottled water is actually pure.
Despite all the scariness here, keeping healthy isn’t all that hard. In places with bad water, local people usually avoid dangerous food. Just be a little smart and you’ll be fine. It’s when you are living long term and start getting lazy with water at home that people get in trouble.
This. Only case of Montezuma’s Revenge I ever got from dozens of trips to Mexico was the time I forgot and they put ice in my Bloody Mary.
Never again. I won’t even trust the water in Detroit, much less some corrupt, blighted hellhole. But I repeat myself. 
It’s very common in Thailand, but usually only at Thai-oriented places. They’ve learned that farangs (Westerners) don’t like it, but even in farang-oriented places they’ll sometimes ask if you want ice in it, because the weather is so damned hot.
But again, it really is silly to worry about ice cubes in Bangkok or pretty much anywhere else in Thailand. The ice companies here have good quality standards.
When I was in Malaysia (Kuala Lumpur), I only drank bottled water but had ice from “Western” or “Modern” restaurants (both independent sit-down eateries and places like McDonalds, Burger King and Kenny Rogers Chicken Roaster) without any issues at all., but avoided ice at anywhere that looked, well, “authentic” (for want of a better term) and, on the advice of the people I knew there, avoided the tap water too (they told me even they didn’t drink it if they could help it). In Singapore, I drank the tap water on a couple of occasions because I was so very hot & thirsty, and didn’t have any problems afterwards.
One of the best pieces of advice my Dad (a seasoned traveller) has given me is this: “Son, wherever you are in the world, there are always two things you can safely drink - bottled Coca-Cola, and the local (commercially produced) beer.”
So far I’ve found that to be excellent (and often-followed) advice. 
For the folks up thread that believe an illness was caused by ice in drinks, how did you arrive at this conclusion?
Maybe you hadn’t eaten all day, so it wasn’t the food?
As I mentioned up thread, ice for beverages is made with purified water.
But delivery of the ice is another matter. Very, very, very seldom have I seen a bartender use tongs to put ice in drinks. Maybe once. Always bare hands are used. These are the same hands that make change, pocket tips, scratch the groin, wipe buggers, etc.
What was the condition of the glass? I have seen some places just rinse the glass with water.
So, unless a scientific method was used to determine that in fact it was the ice, I am skeptical about it.
I avoid places that don’t have soap in the bathroom. And I always bring my own, and leave it in the bathroom.
I was at one cantina where they served finger food with the beer. I excused myself to wash my hands. A local said, “You don’t wanna do that. That is where the flavor is.”
In some places. I find it hard to believe that it’s a universal practice outside tourist areas of certain countries.
I am reporting what I have seen in my 8 years in the Yucatan peninsula. Outside of the peninsula, I don’t have much information.
It is a universal practice throughout Thailand, even outside the tourist areas. If you get sick here, chances are very high it was not the ice.
Having lived in and traveled around Asia for the better part of the last three decades, I’d have to say that, outside of Japan, Singapore, and South Korea, that’s been my experience also. Most especially in the Philippines, I never accepted a drink of any sort in a glass. When I ordered a drink and the waitress asked me if I wanted it in a glass, I’d always request the drink in a bottle, saying, “It already comes in a glass!”
Living in Beijing now and I still won’t order anything–not even water–in a glass.
So you take that bottle, with who knows what history, and put the neck into your mouth?
The simple fact is that for the most part, we have little or no control over what we ingest unless we prepare it ourselves. Drink only bottled water…? Are you absolutely sure that the shopkeeper isn’t refilling the bottles from the tap and putting a dab of superglue to simulate the feel of a breaking seal? Do you inspect the kitchen and take swabs from the staff at any place you eat? Do you always wear gloves so that you will not touch a contaminated surface and then your eye? I won’t go in to the dangers of having sex…
Of course you don’t.
I know its a zombie, but this is with respect ridiculous. Any ice factory which got a reputation for making its customers sick with its products would go out of business, tourist or no tourists.
There are two types of pathogens that you could face. Dangerous ones like EColi, which are going to be as bad for the locals as for you, living in the third world gives you no more immunity to these than living in a warzone gives you immunity to bullets. The second is local bacteria which you immune system does not like because its unfamiliar with them.
In the case of the first, any factory which develops a reputation for causing illnesses, is going to go out of business. In the case of the second, no amount of purification is going to prevent that and that can happen in any country, even in different areas of your own country.
This is an excellent summary, but I would add: bleach (i.e. hypochlorite) is not as strong a disinfectant as iodine. It will kill bacteria, but it won’t kill some eukaryotic parasites (giardia, amoebas, etc.) which can form chlorine-resistant cysts. (I believe filtering takes care of these). When I was a Peace Corps Volunteer we were taught three ways to purify water: boiling, filtering + chlorine, or iodine. (Using iodine long term to purify your water can be toxic as well).
For what it’s worth, I didn’t use any of the three methods when I lived in my village- I got my water from a fountain that came from deep underground, so it was safe to drink. I often drank tap water in cities as well, and I got sick on occasion but I wasn’t sick on a regular basis. Most cities, even in developing countries, do make *some *effort to purify water, which is why life expectancies even in the poorest African countries are longer than they used to be a hundred years ago.
KMNO4 in water is also pretty effective.
I grew up in Sierra Leone. Our tap water was stored in a huge tank as the supply was somewhat intermittent. We washed, brushed our teeth and cooked with tap water. All drinking water was boiled and stored in our “American style” fridge in gin bottles.
The UV’s main purpose is against biologicals. The activated carbon is like a supersponge: lots of impurities (including heavy metals) get trapped into its many, many holes.
It’s also worth pointing out that ‘developing countries’ covers a lot of ground. Sierra Leone (and for that matter the country where I was stationed) is pretty much near the bottom of the spectrum of ‘developing countries’ (at least the ones which don’t have current wars). The more advanced ‘developing’ countries (e.g. Brazil or Cuba, or Mexico, or Malaysia) are going to be a world away from Sierra Leone.
:dubious: :smack: