Mexico City’s Reservoirs Are at Risk of Running Out of Water

The system that supplies about 25 percent of the water to Mexico City’s residents is running dry.

Drought, climate change, urbanization, infrastructure issues and other factors are driving down water levels in a group of reservoirs called the Cutzamala system. The system supports 22 million people in the capital city and its surrounding metropolitan area.

“If it doesn’t start raining soon, as it is supposed to, these [reservoirs] will run out of water by the end of June,” says Oscar Ocampo, a public policy researcher, per Vox’s Caroline Houck.

“The water shortage has really intensified this year,” Claudia Rojas Serna, a hydraulic engineer at the Autonomous Metropolitan University in Mexico, says to the Los Angeles Times’ Patrick J. McDonnell. “What we are going through now is as bad as we have seen.”

Mexico City typically experiences dry winters, with a rainy season that lasts from May to early October. Due in part to a combination of human-caused climate change and an El Niño climate pattern that leads to warmer weather, the city has been experiencing higher temperatures and reduced rainfall in recent years.

Between 1991 and 2021, the average daily high temperature for April in Mexico City was 78.2 degrees Fahrenheit. In April this year, temperatures reached 80 degrees on all days but one, and the city hit at least 85 degrees on 15 days. And in 2023, the city received 18 inches of rain, down from an average of 42 inches per year between 1991 and 2021.

“Climate change is changing the [likelihood] of these extreme events,” Sarah Kapnick, chief scientist at the U.S. National Oceanic and Atmospheric Administration, says to Scientific American’s Jordan Kinard.

As a result of the drought, water levels in the Cutzamala system are dwindling. The system was at 28 percent of its capacity in mid-May, a historic low, according to the Washington Post’s Kasha Patel. Millions of people only can turn their water on sometimes, and some only receive running water for an hour or less each week as officials ration the resource. Wealthy residents can buy water from private companies, but for others, that’s not an option.

“In Mexico City, there is a historical and critical issue of inequality in the access to water,” Fernanda Mac Gregor, a climate change researcher at the National Autonomous University of Mexico, tells the Washington Post. “We are already facing many warnings and they will continue to worsen, and not only in terms of water and climate change, but in terms of inequality and poverty.”

Since the Cutzamala system has less water available, officials are taking more water from aquifers under the city to compensate. But that’s causing the ground to sink around five inches each year, Ocampo tells Vox. And the city is consuming more groundwater than its surface water can replace, Juan Bezaury, the former Mexico country representative at the Nature Conservancy, tells Scientific American.

Another factor exacerbating the limited water supply is faulty infrastructure. Between 30 and 40 percent of the water that makes it into the pipes either leaks out or is siphoned off by people illicitly tapping into the system.

Replacing pipes across the city could conserve water by reducing leaks, but it would cost billions of dollars, Gabriel Quadri De la Torre, a federal congressman for the Mexico City district of Coyoacán, tells the Washington Post. “It is very difficult to think that the Mexico City government will have this amount of money to invest in the network.”

Urban planning solutions could help address water shortages, too. Planners could “do a better job of protecting natural environments that allow our aquifers and our groundwater to recharge,” Victoria Beard, who researches inequality in urban planning at Cornell University, says to Vox. Cities should be built “out of materials that allow our groundwater to recharge. We don’t have to smother every inch of our city with these impervious surfaces.”

On Sunday, Mexico elected its first-ever female president, Claudia Sheinbaum, a climate scientist who was previously the mayor of Mexico City. While campaigning, Sheinbaum had emphasized that the country needs a 30-year plan for managing water.

Water shortages are not limited to Mexico City. Similar crises have affected Cape Town, South Africa, and São Paulo, Brazil, among other places. And with water levels in the Colorado River basin dwindling, the American Southwest has been facing cuts to water use.

“Water sources are depleted around the world,” Beard tells the Los Angeles Times. “Every year, more cities will face ‘Day Zero,’ with no water in their piped systems.”

Will Sullivan | | READ MORE

Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.