MEXICO CITY (AP) – On a bank of Villa Victoria reservoir, where in other years boats might have used them to anchor, 10 concrete blocks lie exposed to the sun. They should be under water, but that was before severe drought dropped the reservoir to the lowest level that Gabriel Bejarano has seen since he moved back to his grandfather’s farm a decade ago.

“The water is supposed to come up to here,” Mr. Bejarano, a veterinarian, said as he pointed toward a fence a hundred yards back from the reservoir’s edge on a recent morning.

The dipping level on the north shore of this lake near Toluca is a major problem for Mexico City, about 77 miles to the west. Villa Victoria—about one-third its usual level this time of year—and two other drought-depleted reservoirs make up most of the Cutzamala system, which serves more than 20 million people and is at a historical low for this time of year.

Even more worrisome: Mexico’s rainy season is just about over, and its departure will end any realistic hope of refilling the reservoirs before next year. The Mexican National Water Commission on Tuesday announced water restrictions equivalent to about 8 percent of the Cutzamala system’s flow, and millions of users in Mexico City and Toluca fear even greater restrictions over the winter.

Mexico City gets more than a quarter of its water from those reservoirs. Most of the rest is drawn from the Valley of Mexico’s increasingly depleted aquifer. Neighborhoods without as many wells—thus more reliant on the reservoirs—will feel the shortages first and most acutely.

The drought hasn’t been limited to the valley. Seventy-five percent of Mexico is currently in drought, according to the most recent data from the country’s National Meteorological Service, including “extreme” drought across much of Central and North Mexico and some “exceptional” drought in the states of Durango and San Luis Potosí. The government has distributed emergency water by truck in Durango throughout the summer, plus almost 40 million liters of water across eight other drought-stricken states.

Meanwhile, navigation and tourism on Lake Patzcuaro, known for iconic Day of the Dead celebrations in the western state of Michoacan, risk drying up with increasingly low water levels.

In Mexico City, it is not unusual in recent years to see some water shortages just before the rainy season. In spring 2021, Villa Victoria was at one-third its normal capacity in what then-Mayor Claudia Sheinbaum described as the city’s worst drought in 30 years. But summer rains largely alleviated that drought, part of a weather pattern where warmer months typically usher in low-pressure weather systems that bring rain.

But that pattern was disrupted this year as El Nino conditions created a wind shear over the Gulf of Mexico, Tereza Cavazos, an oceanography professor with the Ensenada Center for Scientific Research in Baja California, told The Associated Press.

The window for rain to replenish the system is quickly closing, according to Manuel Perlo Cohen, an urban planner and urbanism professor at the National Autonomous University’s Institute of Social Research. The best of the rainy season is already over; Mexico’s November and December rainfall is typically less than a tenth of what falls in summer months.

“I’m sure we’re going to have a shortage problem and I’m sure the city will get less water and many inhabitants will suffer from that,” Mr. Perlo said.

Fixing Mexico City’s notoriously leaky water system would help in times of drought. Academics at the National Autonomous University in 2018 calculated the system leaks 5,680 gallons per second. Ms. Sheinbaum, now a leading presidential candidate, tried to address the leakage while mayor but progress has been slow.

Mr. Perlo said fixing what he called the world’s “largest and most complicated, sophisticated infrastructure for access to water” will be expensive, and there hasn’t been funding to do so.

“We shouldn’t be facing these kinds of situations,” he said. “We have enough water and we’re not using it efficiently.”

Some advocates have suggested restoring Mexico City’s last remaining natural watercourse, the Magdalena River, but that would have to contend with pollution along the river’s entire length from its source west of the capital.

Much of the city relies on wells that tap into the valley’s groundwater. In response to the cuts on Tuesday, the government said it would drill new wells. But it may be hard to find enough water that way, especially as less water is returned to the valley’s overexploited aquifer.

“Mexico City is a monster; it’s a beast,” said David K. Adams, an atmospheric scientist with Mexico’s National Autonomous University. “All the asphalt, all the plastic in the gutters means that water disappears. It never enters the system” by reaching the aquifer, he said.

The government is also working on a new water treatment plant at the Madín reservoir, just northwest of Mexico City, which will add 132 gallons per second to the Cutzamala system.

“That’s not a medium- and long-term solution,” said Mr. Perlo. “We cannot be living on the edge all the time.”

Another solution could be local-level water capture.

Working with Mexico’s Environment Department, Isla Urbana, a group working to improve water access in the city, has installed 10,000 rain collection systems house-by-house across the traditionally underserved southern boroughs of Tlalpan and Xochimilco. The systems gather, filter and treat rain falling on a building before storing it in a personal tank.

Emilio Becerril, Isla Urbana project manager, said such rainwater harvesting could “permanently change the water access situation.”

But a lasting solution needs institutional changes, he said.

“Even if you build thousands of systems, there are thousands of houses being built—more and more extractive,” said Mr. Becerril.

Mr. Perlo’s department at the university built a four-hectare rain capture system into a playground in the southeast borough of Iztapalapa in 2018. Last month Mayor Martí Batres proposed to build thousands of rainwater harvesting systems into schools across the capital, a program Mr. Perlo hopes doesn’t succumb to the same money issues as previous government water plans.

Mr. Becerril also wants to see wastewater reuse, and new infrastructure to separate stormwater from waste: an idea even he admits straddles the line between “hopeful” and “delusional.”

“Rain patterns are changing. It’s the first year I personally have seen that clearly,” said Mr. Becerril. “We’ve gotten to the urgency point.”

Mr. Bejarano, the veterinarian living on the edge of the Villa Victoria reservoir, said he worries less about water for his grandfather’s farm and more about younger generations like his son, who wore a Sonic the Hedgehog hoodie as his father carried him around the property in one arm.

“We all have children,” he said. “We’re all affected, especially when it comes to water.”