The problem of the floods in the Valley of Mexico is analyzed, from a historical point of view that essentially shows that this problem is recurrent since the epoch of the Aztecs. The solution that always has been looked for should not imply to relent the urbanization of the valley, but it is also true that the solutions have not been preventive. They have been developed after catastrophic floods. In the present times, there is an important delay in the works. Specially in the capacity of discharge out of the street works. If this delay is not corrected, there is a high risk of a massive flood in the next years. Finally, it is established that the urban growth in the Valley of Mexico should be stopped, because it is very difficult to improve the services for the actual population and it would be impossible to do it with a increasing amount of people.