The correct answer to this open question is the following.
Although you did not attach the link to the video, we can comment on the following general terms.
Mexico City residents are adapting to water scarcity in the following ways. I have family that lives in Mexico City, and they frequently talk about what the local government takes action to help mitigate with the water scarcity issue. One of the most important decisions is that Mexico City is divided in different counties. These counties have water weekly water reductions on weekends to save water. So each month, counties have these reductions Saturdays and Sundays. So people fill their home water tanks Thursdays or Fridays because they know there will be no water until Tuesday.
The water supply system in Mexico City is called the "Cutzamala System." The water comes from another state, Mexico State, and runs hundreds of kilometers to supply the water needed for 20 million people that live in Mexico City and the metro area that belongs to another state: the state of Mexico.