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Sinking Cities: Why Parts of Phoenix—and Much of Urban America—Are Slowly Dropping
A new study confirms Phoenix and 27 other U.S. cities are sinking—putting millions of people and buildings at long-term risk.
Phoenix is sinking. Not metaphorically, but literally. According to a 2025 study published in Nature Cities, Arizona’s capital is subsiding at an average rate of 0.8 millimeters per year, with some areas dropping by up to 2 centimeters annually. While that might sound minor, the implications are anything but.
The study, which analyzed satellite data across 28 major U.S. cities, revealed a troubling trend: every single city examined is experiencing some form of land subsidence. And the causes are largely human-driven.
📉 What’s Happening Beneath Phoenix?
The ground beneath Phoenix is slowly compacting due to a combination of natural and human-induced factors. Chief among them is groundwater depletion. Over the past century, large-scale pumping of underground aquifers caused the soil above to compress. While Arizona implemented the Groundwater Management Act in 1980, and water use has since stabilized, the lingering impact of past overuse remains.
Some areas in the Phoenix metro region have already experienced up to 18 feet of subsidence over the last 40 years, and the newly published data shows that areas housing 1.4 million people and 113,000 buildings remain at moderate to high risk of structural damage.
🌆 Sinking Cities Across the U.S.
Phoenix isn’t alone. The Nature Cities study revealed that nearly 34 million Americans live on land that is subsiding, and over 29,000 buildings nationwide sit in zones of high or very high risk.
Here are some key findings from other cities:
Houston, TX is the most affected, with 42% of its area sinking more than 5mm/year and localized zones dropping up to 5 cm annually. Dallas–Fort Worth, New York City, Chicago, Los Angeles, and Denver are also seeing significant ground shifts. Even cities you might not expect—Portland, Boston, and Philadelphia—are experiencing measurable sinking, largely due to natural geologic changes or compaction from development on soft soils.
🛠️ What Causes Subsidence?
There’s no single cause, but several primary drivers are contributing:
Groundwater Overuse: This is the dominant factor in most regions, especially in arid and agricultural areas. Oil and Gas Extraction: Particularly in Texas, removing underground fossil fuels causes the surface to sink. Post-Ice Age Rebound Effects: In northern cities like Chicago and New York, the land is still adjusting from glacial movement thousands of years ago. Urbanization: The weight of skyscrapers, concrete, and infrastructure can compress soft soils underneath. Landfill & Soil Compaction: Areas built on old lakes, wetlands, or landfills—common in coastal cities—are inherently less stable.
⚠️ What’s at Risk?
The consequences of even slow land subsidence can be serious:
Building damage: Foundations can crack, tilt, or become unstable. Infrastructure stress: Roads, pipelines, and electrical lines can be misaligned or fractured. Flood risk: As land sinks, especially in coastal cities, the risk of storm surge and sea-level rise intensifies. Water infrastructure: Subsidence can affect aquifer storage and groundwater recharge.
✅ What Can Be Done?
While stopping subsidence entirely is nearly impossible, smart urban planning and resource management can mitigate the damage:
Limiting groundwater use through stricter regulation and conservation. Investing in resilient infrastructure designed to adapt to ground shifts. Monitoring subsidence hotspots with regular satellite data. Educating the public and developers on long-term land risks before building.
🧭 Final Thoughts
Phoenix’s slow descent is a reminder that cities are not static—they live, breathe, and shift over time. As climate change and population pressures increase, the invisible motion beneath our feet demands more attention. Cities that plan for it now will stand taller in the decades to come—even if the ground beneath them doesn’t.
Related Articles:
Yes, Phoenix Is Sinking. What Does That Mean for the City? – Phoenix New Times
Cities Are Sinking Across the U.S. – CBS News
Why Houston and New York Are Sinking Fast – Business Insider
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