What’s wrong with the water in Mexico?
Many people thinking of traveling to Mexico for the first time ask this question. The short answer: nothing.
The problem isn’t the water itself; it’s how it’s managed. In many parts of Mexico, city water is not available 24 hours a day, seven days a week. The city water supply may be made available in one area for a few hours a day and then the water supply is routed to another area. I remember a trip to Playa del Carmen many years ago, we stopped at several different resturants having a beer and a shot of tequila before checking for water in the restroom before ordering food. Finally there was water at the fifth resturant, at least I think there was. You can imagine things were getting a little foggy by that time.
To have water available all the time at a house or business a cistern (cisterna) is buried underground to provide a reservoir of water. The cisterna is the first order of business when building a new home. The water has to be made available for mixing concrete, cleaning up tools, etc. Cisternas vary in size from 1200 liters to 10,000 liters with the water level being controlled by a float system just like in a toilet tank.
From the cisterna, the water is pumped to another container on the roof called a tinaco. The tinaco is attached to the plumbing system and the water is gravity-fed throughout the house. The water level in a tinaco may or may not be controlled. If not, a timer is added. The other way to know when the tinaco is full is to turn on the water and let it run. When water runs off the roof of the house, the tinaco is full.
The height of the tinaco is important. Gravity-fed systems generate about one half PSI per foot of elevation of the source. So on a one-story house, the tinaco may be only five to six feet above the shower, giving about three PSIs of water pressure, much lower than we are accustomed to in the states.
OK, but what’s wrong with the water? The cisterna and tinaco are open to the atmosphere allowing the introduction of bacteria. There are two types of bacteria, aerobic (with air) and anaerobic (without air). In the states we have closed systems, no air, so our bodies are accustomed to small amounts of anaerobic bacteria. With the cisterna and tinaco being open to the atmosphere, aerobic bacteria, once introduced, multiplies and gets to the point that it will cause illness. The closed systems minimize the bacteria in the states since bacteria cannot be introduced; what bacteria comes from the water plant can still multiply.
Since bacteria is everywhere, there really is no way to avoid it completely. The problem is not so much the bacteria as it is that it’s different bacteria than what you’re accustomed to and your body doesn’t know how to cope. The good news is that it only takes a few trips down to build up some resistance to the bacteria. You’ll never be immune, just not as susceptible. Just remember the Vermox from the local farmacia.
A version of this article previously appeared on the Facebook page for the beautiful Casa Tranquila in Chelem, Mexico. It is republished here with permission.