The sidewalks are usually among the first to crack. The streetlights tilt, ever so slightly. You can barely even see it with the naked eye. Some brick walls can splinter, but even if they do, most homeowners just chalk it up to age. But in cities across the US, this has a common cause: subsidence.
According to a sobering new study published in Nature Cities, all of the 28 most populous cities in the United States are all experiencing land subsidence. This subsidence (slow, often imperceptible sinking of the ground) is not due to earthquakes or erosion. It’s largely because we’re pumping too much water from underground aquifers, draining the very foundations our cities are built on.
34 million Americans live on sinking land
Land subsidence is an old, familiar threat. It can be caused by geological forces, particularly in coastal and karst areas. But increasingly, it’s human activities that are starting to trigger subsidence.
Until not that long ago, it was hard to study widespread subsidence. You could identify it locally, but a big picture was hard to draw. But thanks to satellites (in particular, European Space Agency’s Sentinel-1 satellites), we can now study subsidence from outer space. That’s good news, but the results are anything but good.
The new research looked at all US cities with a population greater than 600,000 people. In 25 out of 28 cities, more than 65% of the urban land area is sinking. And in cities like Chicago, Dallas, Fort Worth, Columbus, Detroit, and New York, that number jumps to over 98%.
The land isn’t just lowering a fraction of a millimeter here and there. In Houston—America’s fastest-sinking major city—42% of the area is subsiding faster than 5 millimeters per year. Entire neighborhoods are dropping more than a centimeter annually. That’s like losing a foot over 30 years.
These aren’t just marginal zones, either. Airports, highways, high-rise buildings—critical infrastructure is sitting atop this slow-motion disaster. New York’s LaGuardia Airport? Sinking. Parts of San Francisco? Sinking. East Potomac Park in D.C.? Yep, that too.
Thirsty cities
So why is this happening? A part of this is the expansion of our urban areas. We’re putting more and more weight on soils, compacting them. Some parts of cities are also expanding into areas that were naturally sinking.
But the biggest impact, this study says, is water; or rather, the lack of water. Simply put, we are using more water than the Earth can naturally replenish.
The vast majority of water we use is groundwater. When cities pull water from underground aquifers, they lower the water pressure that keeps the ground stable. Think of it like deflating a balloon—the soil above it compacts, and the land sinks. This is especially true in confined aquifers, where the groundwater is trapped between layers of clay and rock. Once the water is gone, the collapse can be irreversible.
The researchers found a strong statistical correlation between declining groundwater levels and land sinking in 13 cities, especially in New York, San Diego, Houston, and Memphis. In New York and San Diego, up to 76% of vertical land movement could be explained by changes in groundwater pressure.
In some places, the problem is made worse by geology. In San Diego, for example, the aquifers are so permeable that even small drops in water level lead to quick, large subsidence events. In Washington, D.C., by contrast, the bedrock is stiffer. This doesn’t make it immune, but offers a bit more resilience.
How bad is it for regular folk?
The study estimates that over 29,000 buildings are located in zones of high or very high risk due to ground deformation. Many are in areas where differential land motion (one side of a building sinking faster than the other) can silently weaken foundations, crack walls, and compromise the integrity of homes, bridges, and roads.
Some of the cities with the highest proportion of at-risk buildings include San Antonio, Austin, and Fort Worth, where between 1 in 45 and 1 in 143 buildings may face significant structural threats from subsidence. Even a small angular tilt—just a fraction of a degree—can render a structure unsafe over time. In this sense, a sinking of one centimeter per year can be devastating.
There’s a great deal of variety between different cities and even different neighborhoods between the same city. Much depends on the foundation type, soil composition, construction methods, and maintenance. But the risk is real—and it’s being underestimated.
We’re already starting to see this. In recent years, building collapses have raised alarms about the vulnerability of aging urban infrastructure. But much more damage is happening without being obvious. In fact, many subsiding areas don’t look visibly dangerous until it’s too late. The authors of the new study suggest that land subsidence may be playing an unrecognized role in weakening structures across the country.
Can we stop this?
As mentioned, some causes are natural and geological. There’s not much we can do about that. But much of the problem is man-made. And that means we can take action.
Better groundwater management is the first and most obvious step. That could mean stricter limits on pumping, incentives for conservation, or investment in technologies like managed aquifer recharge, where surface water is deliberately stored underground during wet seasons.
Cities also need to map and monitor their subsidence risks in detail, incorporating this data into zoning decisions, building codes, and infrastructure planning. What’s safe to build today might not be stable tomorrow, and satellite measurements can only get you so far. Local, detailed studies can capture much more detail.
And adaptation, too, has a role to play. In flood-prone areas, subsidence can make storm surges and heavy rains even more devastating. Building smarter drainage systems, elevating critical infrastructure, and enforcing no-build zones in high-risk areas can buy time.
But most importantly, the report urges city planners and policymakers to take subsidence seriously.
The study was published in Nature Cities.
