Montezuma's Revenge != good. (Montezuma's Revenge <> good).

water from anywhere can be bad. if the area has a poor sewage systen or shallow wells, limited water supply or lack of transportation (piping ) the water could easily get tainted. Not only in Mexico but anywhere. Often when visiting a different area, people get sick of upset stomach due to being exposed to different types of virus, than accustom to.

Guess what? The raw (untreated) water from Mexico is just as bad as the raw water in the US. The problem that many people have when travelling in Mexico is that the local water suppliers can seldom provide the level of water treatment that US citizens take for granted. There are two reliable sources of water: surface water (rivers, lakes, ponds, etc) and ground water (aquifers). Ground water tends to be cleaner than surface water because it's harder to pollute; the earth does have some filtering ability. Surface water is easily polluted by agricultural runoff (fertilizers, pesticides, animal wastes) and human activity (raw human sewage, street runoff, etc). The biggest culprit for intestinal problems in some water in Mexico is biological. Water treatment plants are designed to kill and remove biological agents but this can be an expensive process. Water treatment plants require lots of space and power to run the raw water through the treatment process. This means lots of money, which is gotten through water fees. The natives generally grow up with the local water and have may develop a natural tolerance for whatever bacteria may be in it. They may see no need to pay for treated water when they can put up with what they have for free. Trot down to your local stream and take a big drink..I dare you. Odds are good you'll get ill from something in the water. You'll have no tolerance for whatever made you sick since you only drink the highly polished product that comes from the tap. Mexicans want clean water, too. There are several pilot programs that are providing small communities with solar-powered units that use UV light to treat water for biological contamination. Solids filtering is done with large holding tanks; keep water still for a few hours and almost everything in it will settle to the bottom. The upfront cost is modest, maybe $2000-$3000 for units that can deliver 500 gallons per day, but it's still way out of reach for the poor communities that need it the most. In short, the water in Mexico is generally bad for people who live in areas that provide treated water for its residents. Mexican water can be better, but it's a matter of access to treatment facilities.

Some water from Mexico can cause intestinal trouble for foreigners, but water treatment is getting better and better there. I've been to four locations in Mexico, drank the water and never had a problem.

&quot;You bet your sweet bippy". Never drink it, never eat their food, never drink their beer, never ingest anything made or grown in Mexico. If you do, you will PAY, BIG TIME.