Claudia Sheinbaum won a commanding victory in last month’s Mexican presidential election, winning almost 60 percent of the vote and securing legislative majorities for her left-wing Morena party. A former climate scientist and mayor of Mexico City, Sheinbaum dominated the polls after emerging as the successor to the popular outgoing president, Andrés Manuel López Obrador.

Even as Sheinbaum prepares to take office, the city she ran between 2018 and 2023 is making global headlines as it suffers through a historic water crisis. Millions of low-income residents across the city rely on intermittent deliveries of contaminated groundwater, and even wealthier neighborhoods have seen their taps shut off as the city’s key reservoirs run dry. Not only that, but the city loses around 40 percent of its water supply to leaks in its underground pipes.

Sheinbaum tried to tackle these problems as mayor, pursuing projects to capture rainwater, restore depleted aquifers, and replace and upgrade aging pipes. But water experts and public officials who worked with Sheinbaum say she lacked the resources to turn around a crisis that has been decades in the making. The new power she will have as president, plus a wave of new leadership in the local and regional governments of Mexico City, could usher in a sweeping change in how one of the world’s most populous countries manages its water and adapts to climate-fueled drought.

“Water is her main concern,” said Armando Alonso Beltrán, the head of the water department for the state government in the Mexico City region and a friend of Sheinbaum’s. “It’s in her top priorities, and it always has been.”

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Enrique Lomnitz, an engineer whose company, Isla Urbana, has built rainfall harvesting systems across the city, agreed that Sheinbaum made significant progress as mayor, but said the city still has a long way to go.

“She has a very good record, and she started a lot of paradigm-shifting programs that opened new possibilities for approaching the water crisis,” he told Grist. “But these are still very small things compared to the scale of the problem.”

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That’s because Mexico’s water crisis is really several different crises. The shortage that captured global headlines this spring came about due to an extreme drought caused by the El Niño climate phenomenon. When spring rains failed to arrive, several key reservoirs that supply water to the city emptied out, forcing city officials to implement rotating water shutoffs in the wealthy neighborhoods that are fortunate enough to have consistent running water.

But these reservoirs only supply around 30 percent of Mexico City’s water, most of which goes to the wealthier neighborhoods in the city center. The rest of the metropolis draws water from underground aquifers that have been dwindling for decades, so much so that parts of the city have sunk by several feet. The water that does still come out of these aquifers is often contaminated with toxic chemicals.

A man carries a barrel for water in the Iztapalapa borough of Mexico City. The city has experienced a worsening water crisis for decades as underground aquifers run dry.
A man carries a barrel for water in the Iztapalapa borough of Mexico City, which has seen a water crisis worsen for decades as underground aquifers run dry. Gerardo Vieyra / NurPhoto via Getty Images

The problem is not that there isn’t enough water to recharge these aquifers over time: Mexico City gets around 34 inches of rainfall a year, similar to Midwest states like Iowa. But the city has grown by millions of people in recent decades without investing in infrastructure to capture and distribute all that water. The critical forest that recharges the aquifer, known as the “Bosque del Agua” or “water forest,” has diminished over the past century due to logging and development. Meanwhile, the water authority has failed to maintain the residential water system, which has resulted in an astonishing amount of water being lost to leaks — more than 40 percent of the total water supply, one of the highest rates in the world.

Sheinbaum faced all these problems as mayor of Mexico City. In 2019, less than a year into her tenure, she announced a major effort to control these leaks, deploying dozens of “leak response brigades” that would locate and plug holes in the water grid. It’s hard to gauge how successful she’s been, said Lomnitz, because fixing a leak in one part of the system can increase water pressure in another part of the system and thus cause more leaks. And as the city sinks thanks to aquifer subsidence, more leaks appear.

“There’s like a Whac-a-Mole kind of thing happening,” said Lomnitz. “You fix the leaks here and they increase over there.” Despite Sheinbaum’s investment, the city is likely billions of dollars away from meaningful water savings from leak reduction.

“There were mixed results, mostly positive, from her time as mayor,” said Alonso. “But it’s hard to tell the final results, because the drought came last year and there was less water.”

Making the city “spongy” enough to catch and store falling rain is even harder given Mexico City’s idiosyncratic history. The city lies on a former lakebed that early Spanish colonists drained in the 17th century, and as a result it is prone to frequent flooding. The city’s leaders have spent the equivalent of billions of dollars over the past hundred years to build tunnels that can drain this floodwater away from the metropolis, including a massive 38-mile tunnel project that opened in 2019.

“Our issue has always been how to take out water from the city, and as we had this very rich aquifer and this amount of rain which is quite good, we never had this problem of scarcity,” said Loreta Castro Reguera, an architect who has worked on a number of water projects in Mexico City. The city also has a problem of “technological inertia” as it seeks to capture and harvest rainwater, added Castro Reguera: It uses the same tunnel system to flush out stormwater and sewage, which makes it almost impossible to treat and reroute rainwater for residential usage.  

Since building a parallel pipe system for stormwater would be almost unthinkably expensive, the city’s best option is to start smaller, capturing rainwater at the household or neighborhood level. Sheinbaum started doing this as mayor through a number of innovative nature-based projects. For instance, the city transformed a former landfill near the city’s largest wastewater treatment plant into a restored wetland that filters and treats captured stormwater, yielding a new high-quality water supply. She also worked with Lomnitz’s Isla Urbana to install thousands of household catchment systems and boosted the budget for infrastructure repairs.

Another model comes from Sheinbaum’s incoming successor as the mayor of Mexico City, fellow Morena member Clara Brugada, who has her own record tackling water issues. Brugada, who will take office later this year, has served for almost a decade as the mayor of Iztapalapa, a large impoverished borough in the eastern part of the city. Iztapalapa has struggled for decades with crime and water shortages, but Brugada took major steps to replace faulty infrastructure and created several community spaces known as “utopias” that combine green space with free public services and recreational areas.

One of the banner projects in the borough was La Quebradora, a “hydraulic park” designed by Castro Reguera’s firm with support from the local government. The park captures stormwater to reduce flooding in nearby areas and funnels that water down into the aquifer, recharging groundwater and easing the local water shortage. 

“The impulse needs to come from the government,” said Castro Reguera, describing the need for more projects like the one in Iztapalapa. “This might be a chance to put more of these projects in place.”

Incoming Mexico City mayor Clara Brugada, left, stands with Mexico's president-elect Claudia Sheinbaum during an election celebration. Both politicians have received praise for tackling Mexico City's water crisis.
Incoming Mexico City mayor Clara Brugada, left, stands with Mexico’s president-elect Claudia Sheinbaum during an election celebration. Manuel Velasquez / Getty Images

Sheinbaum, however, will have to worry about water issues in areas far from Mexico City, because the country’s northern states are facing a very different water problem than the capital. In these states, which are much drier than the region around Mexico City, the problem is less poor management than it is a lack of supply. The vast majority of water in these areas goes to irrigate crops such as avocados and alfalfa, and another share supplies numerous mining operations, leaving very little leftover for residential use. 

Sheinbaum and her predecessor López Obrador have tried to tackle this problem by curbing so-called water concessions, which grant farms and mines the exclusive right to tap rivers and aquifers. Before the election, López Obrador pushed a constitutional amendment that would have allowed the government to cut off water to mines during a drought, and Sheinbaum has signaled she, too, will support that measure. She has also reportedly called for a revamp of the national water law that would limit water use by farms, though this effort will likely face opposition from powerful agricultural interests. (Neither the president’s office nor the campaign offices of Sheinbaum and Brugada responded to Grist’s interview requests.)

In these northern states as well as in Mexico City, the water crisis is as much a problem of governance as it is one of physical shortage. The country’s national water authority has faced accusations of bribery and corruption for years, and the local authority in Mexico City has faced criticism as well for a lack of transparency about water quality. These are the same utilities that Lomnitz says have underinvested in infrastructure for decades.

But the conditions are ripe for a surge of investment. Sheinbaum holds the presidency, which will give her access to a much larger budget to invest in water storage and treatment projects. Brugada has promised to continue her focus on rainwater harvesting and environmental justice as the mayor of Mexico City. The new head of Mexico City’s regional government is also a member of the Morena party, and which means all the levels of government are aligned for the first time in decades.

Victor Magaña Rueda, an environmental scientist at the National Autonomous University of Mexico who has studied climate impacts in Mexico City, told Grist that he believes Sheinbaum has the political will to turn around the trend of disinvestment and delay.

“She has a very profound knowledge of what the water crisis in Mexico is,” said Magaña. “She is more interested in environmental problems I would say than our president right now. But the important thing is that she knows that we cannot go on in a situation like we lived in for the past few years.”