Walk down Mission Street today and you’ll see it. It’s a 58-story luxury skyscraper that looks, at first glance, like every other glass-and-steel giant in the South of Market district. But local residents and structural engineers know it by a different name: the leaning tower of San Francisco. It is officially the Millennium Tower, a $350 million project that was supposed to be the crown jewel of West Coast urban living. Instead, it became a punchline, a legal nightmare, and a massive engineering headache that has cost hundreds of millions of dollars to fix.
People often ask if it’s safe. The short answer is yes, according to the city’s building experts, but that doesn't make the numbers any less terrifying. By 2016, only seven years after it opened, the building had sunk 16 inches. It wasn't just sinking straight down, though. It was tilting.
Engineering isn't always about perfection. It’s about managing variables. But when a 645-foot building leans more than two feet at the top, people notice. You’ve got residents reporting cracking sounds in the middle of the night and popping noises from the facade. It’s the kind of thing that makes you want to keep your bags packed, even if you paid $5 million for your condo.
Why the Building Started Sinking in the First Place
The technical reason for the tilt is actually pretty straightforward, even if the legal fallout wasn't. Most of the massive towers in San Francisco’s Financial District are anchored into bedrock. We're talking 200 feet down through the soft Bay mud and sand. The developers of the Millennium Tower, Millennium Partners, made a different choice. They used a "friction pile" design.
This meant they drove 950 reinforced concrete piles about 60 to 90 feet into the dense Colma sand layer rather than going all the way to the rock. At the time, they argued this was a standard practice and perfectly safe. They weren't technically wrong—plenty of buildings in the city use similar foundations—but the Millennium Tower is exceptionally heavy. It's a concrete structure, not a lighter steel frame.
Then there’s the "Transbay Transit Center" factor. The developers blamed the neighboring construction of the massive transit hub for the sinking. They claimed that the "dewatering"—the process of pumping water out of the ground to dig the transit center’s foundation—weakened the soil under the tower. Basically, they argued the neighbor sucked the straw out of their milkshake. The Transbay Joint Powers Authority, of course, said the tower was already sinking before they even broke ground.
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The Numbers Are Kind of Wild
When you look at the data provided by the lead structural engineer of the fix, Ronald Hamburger of Simpson Gumpertz & Heger, the scale of the movement is hard to wrap your head around. By the time the "Fix" (officially known as the Perimeter Pile Upgrade) was in full swing, the building had tilted about 29 inches to the west and several inches to the north.
Think about that for a second.
If you dropped a marble on the floor in one of those upper-floor penthouses, it wouldn't just roll; it would take off. Some residents even complained that they could feel the slant while walking across their living rooms. It’s not just an aesthetic issue or a "feel" thing. When a building tilts, the elevators can start to bind in their shafts. Plumbing lines can experience stress. Window seals can pop.
The $100 Million Band-Aid That Actually Worked
Fixing a leaning tower in the middle of a dense city is a nightmare. You can't just jack it up like a car. The solution was to install 52 new piles—this time made of steel and filled with concrete—and sink them all the way down into the bedrock. This is what engineers called "underpinning."
The process was grueling. In 2021, the fix actually made the lean worse for a moment. As they were drilling, they disturbed the soil even more, and the building tilted another inch or two in just a few weeks. They had to pause everything. It was a PR disaster. Imagine being the guy in charge of fixing a leaning building and having to tell the press, "Actually, it leaned more today."
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Eventually, they figured out a lower-impact drilling method. They finished the "bedrock tie-down" in 2023. They basically used the new piles as a lever to pull the building back toward level and, more importantly, stop it from sinking any further. It worked. The building is now anchored to the earth's crust, effectively ending its life as a sinking ship.
What Most People Get Wrong About the Safety
The media loves a "falling skyscraper" narrative. It sells papers. But honestly, the Millennium Tower was never in imminent danger of toppling over. Modern buildings are incredibly resilient. Even with the lean, the structure itself remained sound.
The real danger was the loss of value. Imagine owning a luxury condo that you can't sell because no bank will issue a mortgage on a "leaning" property. The lawsuits were endless. We’re talking about a massive consolidated "megasuit" involving homeowners, the developers, the city, and the transit authority.
- The Settlement: In 2020, a confidential settlement was reached. It included about $100 million for the repair and additional millions to compensate homeowners for the lost value of their units.
- The Inspection: The city's Department of Building Inspection has kept the tower under a microscope. Every millimeter of movement is logged.
Is it still the leaning tower of San Francisco? Technically, yes. The fix stopped the sinking and corrected some of the lean, but the building isn't perfectly plumb. It’s "stabilized." It’s like a broken leg that has been set with pins; it’s strong now, but the X-ray will always show the history of the trauma.
The Ghost of the Transbay District
The saga changed how San Francisco builds. You won't see another major skyscraper in the SoMa district skip the bedrock foundation anytime soon. The "Salesforce Tower" just a block away goes straight to the rock. The city tightened up its peer-review process for foundation designs because they simply cannot afford another $100 million mistake.
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It’s also a lesson in urban geology. San Francisco is built on a mix of bedrock, sand, and literal trash (the Embarcadero is famously built on old gold-rush ships and fill). When you build that big, you're at the mercy of what's underneath you.
Living in the tower now is a weird badge of honor for some. You get a world-class view, a prime location, and a home that is probably the most heavily monitored piece of real estate on the planet. If that building so much as shivers, a dozen sensors will catch it.
Actionable Takeaways for Real Estate and Engineering
If you are looking at real estate in a city known for seismic activity or soft soil, there are a few things you should actually do:
Verify the Foundation Type
Don't just look at the granite countertops. Ask if the building is "end-bearing" (on bedrock) or "friction-based." In cities like San Francisco or Seattle, this matters for long-term stability and resale value.
Check the "SMR" Reports
Large buildings undergo Structural Maintenance Reports. For the Millennium Tower, these are public record now. If you're buying into a high-rise, you want to see the settlement data. A few millimeters a year is normal. Inches are not.
Monitor Local Infrastructure Projects
Construction next door can affect your property. Whether it’s a new subway line or a neighboring skyscraper, "dewatering" is a real risk for older foundations or those not anchored to rock.
The Millennium Tower isn't going anywhere. It’s stable. It’s safe. But it serves as a permanent, 600-foot-tall reminder that in the world of engineering, cutting corners—or even just following the "minimum" code—can lead to a very lopsided reality. The leaning tower of San Francisco is finally standing its ground, even if it took a decade and a mountain of cash to get there.