In many areas, a shortage of rainfall lowers the water sources from rivers, which means that the water decreases to such a small level that when it’s pumped out, a lot of sediment is also dredged out, and that results in water that is of poor quality.
According to an article in The Guardian, Mexico City alone has more than 6,000 miles of sewer pipes, over more than 100 miles, with 68 pumps working to clean the sewage that flows under the ground. And yet, this system is hopelessly outdated and ineffective, which means that the sewer lines leak, which seeps into the water table that carries drinking water.
Researchers who have analyzed the water in Mexico City have discovered that there are a myriad of bacteria present in much of the tap water that people drink. The bacteria is the cause of gastrointestinal ailments such as dysentery and diarrhea. In fact, some of the bacteria that is found in normal Mexico City drinking water is associated with the kind that is present in feces.