Free Mexico Travel Guide and Travel Information

Why is Mexico City sinking?

Mexico City is drinking itself into the ground

Many of Mexico City’s buildings are seriously leaning because of land subsidence.

Mexico City is sinking. Mexico City’s water balance has an aquifer deficit, which causes the drying up of the heavily saturated clay of the former Lake Texcoco (on which the city rests) and has led to land subsidence.

Mexico City keeps sinking as its water supply wastes away. As the city’s population grows and demand for water increases, the problem only gets worse, and Mexico City continues to sink.

If you pump water out faster than the rainwater can trickle back in, the aquifer runs out. Mexico City already pumps out water over twice as fast as it can be replenished, and the population of the city continues to grow.

All that pumping is literally sinking the city. As the city drains water from the aquifers, empty space is left in its wake.

The ground, now without structural integrity, sags into that void. In some places, Mexico City is subsiding as much as 38 cm per year. For comparison, the city of Venice is sinking at a rate of less than half an inch per year.

Over the last century, experts estimate, Mexico City has sunk around 10 m. The sinking of the city has come to a point where the Zócalo, the main square in the historic city center, is at a lower elevation than Lake Texcoco.

Soft lake sediment underneath the city has made it vulnerable to soil liquefaction during earthquakes.

Buildings are sinking and tilting in Mexico City. Because the sinking is not even across the city, buildings tilt to the side, and pipes break: as a result, repairs and maintenance are expensive.

Slanted buildings leer menacingly over pavements, their doors, and windows no longer in alignment with their friends as if crudely displaced from a grotesque theme park funhouse.

Terraced streets built on level ground now undulate, with wavy gables crowding up against each other in parts, and pulling away in others, while city-dwellers struggle up hilly pavements where once the path was flat.

All over the city, particularly in its historic center, buildings and churches display a distinctive tilt, akin to drunken figures. This characteristic lean is a result of the uneven descent of the land beneath their foundations.

The Metropolitan Cathedral of Mexico City, which took more than 200 years to build, has a leaning chapel and bell tower, propped up by stone wedges to stop the whole thing from crumbling down.

The Angel of Independence was built with 9 shallow steps leading up from the street below. As the surrounding area has sunk, an extra 14 large steps have been added to the iconic monument.

Giant sinkholes open up without warning, swallowing parts of roads.

In some areas, cracks open in the street, and buildings collapse or become too unsafe to inhabit. It’s a chronic threat in Iztapalapa, a poor neighborhood in the city’s southeast, home to some 2 million people.

But why is Mexico City sinking?

The Aztecs came to the Valley of Mexico in 1325. They founded the city of Tenochtitlan in the middle of the lake in 1325. Then a small island on the western side of Lake Texcoco seemed quite a suitable place to live.

Over time, the Aztec Empire became the most formidable force on the continent.

Tenochtitlán was smattered with canals, causeways, and dikes. The channels provided natural irrigation and water management while floating gardens called chinampas kept the city fed as it grew to an astonishing size.

By the time the Spaniards arrived, the city had approximately 300,000 residents.

After the Spanish captured Tenochtitlan, they drained the lake Texcoco. Where the Aztecs built dams and canals, the Spanish blocked them to build roads and expand the size of New Spain’s newly built capital, Mexico City.

The Lake Texcoco basin was fed by underground aquifers. Mexico City was built on bad choices, given that it sits on an unstable clay crust and a band of lava rocks. Clay and lava, almost all paved, are the worst combination.

However, the Spaniards continued to drain the lake system. They started draining the lake and cutting down the forests on its shores, making Mexico City more susceptible to intense flooding.

Groundwater overdraft is depleting the aquifers beneath the city, causing it to sink. Texcoco and all the other lakes are gone, with the exception of a few marshlands and a region of canals in the south of the city.

The bowl-like depressions where the lakes once stood had no natural exit for water, and the denuded forests, whose soils once acted as sponges for flood water, no longer served as a buffer between water and people.

The consequences of the draining were enormous: the area turned semi-arid and currently, the city experiences water scarcity. Soft lake sediment underneath the city has made it vulnerable to soil liquefaction during earthquakes.

Mexico City faces the impact of building on an aquifer. This has been ongoing since the mid-19th century. Although the aquifers are replenished, the rate of recharge is only about 50% of the rate of groundwater extraction.

Mexico City fills up like a cup in the rainy season.

Mexico City suffered severe floods in 1555, 1580, 1604, and 1607 before it was proposed to move the capital inland in 1630. But after some reflection, the authorities decided that the answer was no, and the flooding continued.

Mexico City suffered more serious floods in 1645, 1674, 1691, 1707, 1714, 1724, 1747, and 1763.

One flood was so severe that the entire city was submerged for five whole years from 1629 – yet the city lived on, gasping for air and expanding further across the lakebed between downpours.

Water scarcity and urbanization

By the 20th century, most of the lake had been drained, and flooding became the least of the city’s problems. As Mexico City grew and grew and migrants from surrounding regions arrived, Mexico City became increasingly thirsty.

As more and more water was withdrawn, subsidence began. Subsidence was first noticed in 1891 in the old part of the city but was not studied until 1925. In 1948 it was proved that groundwater withdrawal was causing subsidence.

In 1954, the overexploitation was sufficiently serious that pumping was banned in the city center and wells were moved to the north and south of the basin. Subsidence is now stabilized in the city center but is still a major problem in most parts of the metropolitan area.

The city is built on two different geological foundations.

Some of the land beneath Mexico City was volcanic soil that was fertile and was used by the Aztecs to grow crops. It also absorbed water well: moisture was easily absorbed and flowed into underground aquifers without damaging the soil structure.

But when developers built on the volcanic soil and covered it in concrete and asphalt, water could no longer get through to the soil and filter through to the aquifers on which the city relies.

Other parts of the city are built on clay.

It, unlike volcanic soil, cannot absorb water, but simply places it between layers of clay-like cream between layers of dough. When the cream is sucked out, the layers of dough crack and collapse, overlapping each other.

Now, without the lakes, Mexico City turned to groundwater for drinking water. The groundwater was and still is, stored in the relatively shallow aquifers that lie beneath the lake beds.

Land subsidence has been caused by groundwater overexploitation during the last hundred years and has been up to 9 meters, resulting in damages to buildings, streets, sidewalks, sewers, stormwater drains, and other infrastructure.

In search of water in a now lakeless lake basin, Mexico City began using clay soil while neglecting the beneficial volcanic soil. The city’s foundation, a mixture of both geological types, resulted in uneven and uneven subsidence.

This sinking process results in dangerous cracks and fissures, as well as wavy, hilly streets. At the end of the 20th century, the collapse in the central region of the city reached 10 m, and in the Chalco-Xochimilco sub-basin – 7 m.

The impact of development

But not all of Mexico City was built on the lakebed. Southwest of the city center is a region now known as the Pedregal, which rests on the hardened lava flow. The population of Mexico City tripled between 1950 and 1975.

The Pedregal region was mostly regarded as an uninhabitable rock heap.

Developers saw a gold mine and divided large areas of this southwest area into luxury residential complexes. Hundreds of families in a short time rushed to the Pedregal, built their houses, and founded neighborhoods.

The rapid growth of the southwestern part of Mexico City would have unforeseen consequences for the entire metropolitan area.

Between the mid-1950s and mid-1980s, nearly the entire dark swath of volcanic rock that once covered the Pedregal region—comprising roughly 8,000 hectares, was swallowed up by streets and buildings.

The unique ecosystem was almost entirely paved over. While Mexico City residents endure months of regular flooding during the rainy season in some parts of the city, virtually none of that water makes it underground.

Rapid urbanization has sealed up any permeable surfaces in the city with pavement. The city’s pores are clogged, hindering natural drainage and exacerbating the challenges posed by flooding during the rainy season.

You can read more about the importance of clean and filtered drinking water at Healthy Water Guide or at

Use these tags to read more related posts and reviews:
Let us know if this article was useful for you