New York City is a place where we obsess over things that are tall. We crane our necks at the One World Trade Center or the skinny billionaire towers on 57th Street, but honestly, the most impressive thing about this city is 600 feet under your feet. It’s dark. It’s damp. It’s a massive, echoing concrete cavern that carries enough water to keep eight million people from losing their minds. I’m talking about New York City Water Tunnel No. 3, a project so big, so expensive, and so slow-moving that it makes the Second Avenue Subway look like a weekend DIY project.
It's been under construction since 1970. Think about that for a second. Richard Nixon was in the White House when the first blast went off. We’ve been digging this hole for over half a century, and we aren't even totally done yet. It’s the largest capital construction project in the history of the city, and most people walking over it right now have zero clue it exists.
The terrifying reason we need Water Tunnel No. 3
You have to understand the fragility of the current system. For decades, New York has relied almost entirely on Water Tunnel No. 1 (completed in 1917) and Water Tunnel No. 2 (completed in 1936). They are the city's lifelines. If you’ve ever lived in an old apartment, you know that pipes don't last forever. Now imagine a pipe 17 feet wide that’s been under constant, crushing pressure for a hundred years without a single break for maintenance.
Engineers are, quite literally, terrified to turn them off.
If Tunnel No. 1 failed tomorrow, lower Manhattan and parts of Brooklyn would basically dry up. We can’t inspect them because there’s no way to shut the water off without a backup. That’s why New York City Water Tunnel No. 3 is so vital. It isn't just about growth; it's about survival. It's the ultimate insurance policy. Once it's fully operational, the city can finally—finally—shut down Tunnels 1 and 2 for the first time in history to see what kind of shape they're actually in.
It's a gamble. We are betting that the old tunnels hold out until the new one is completely finished.
Sandhogs and the cost of progress
You can't talk about these tunnels without talking about the Sandhogs. These are the legendary workers from Laborers' Local 147. They are a tight-knit, often multi-generational group of miners who go down into the earth to do work that would give most people a panic attack. It’s dangerous. It's loud. The air is thick with the smell of wet rock and machinery.
Actually, it’s more than just dangerous; it’s been deadly.
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Since the project began in 1970, 24 people have died building Tunnel No. 3. Most of those deaths happened in the early decades, particularly during the grueling work on Stage 1. There’s a somber tradition among the Sandhogs: they don’t like to talk about the risks, but they remember every name. This isn't some sanitized corporate project. It’s a gritty, blood-and-sweat endeavor that has spanned generations. You’ll find sons working the same sections their fathers or grandfathers started.
How you actually build a tunnel under a skyscraper
The scale of the engineering is just hard to wrap your brain around. We aren't just digging a hole. We are carving through some of the hardest bedrock on the planet—Manhattan Schist.
In the early days, it was all "drill and blast." You’d drill holes, pack them with dynamite, blow it up, clear the rubble, and repeat. It was slow. It was incredibly loud. Since then, the city has moved toward using Tunnel Boring Machines (TBMs). These are massive, mechanical worms with rotating cutting heads that chew through the rock. But even with a TBM, you’re only moving a few dozen feet a day.
Then there’s the lining. Once the hole is bored, it has to be lined with concrete to handle the immense pressure of the water. We are talking about billions of gallons of water moving from the Hillview Reservoir in Yonkers down into the city. The pressure is so high that the water moves entirely by gravity. No pumps. Just physics.
The weird journey of Stage 1 and Stage 2
The project is split into four stages. It’s not just one long pipe; it’s a complex network.
Stage 1 was the big one. it runs from Hillview Reservoir, down through the Bronx and Manhattan, and across the East River into Queens. It actually went into service in 1998. If you live in those areas, there’s a good chance some of your tap water is already coming through the first part of Tunnel 3.
Stage 2 is where things get interesting and, frankly, a bit political. This stage covers the Manhattan leg and the Brooklyn/Queens leg. The Brooklyn/Queens section was finished and "watered" in the early 2000s. But the Manhattan leg? That was a saga. For years, the tunnels were dug, but the "shafts"—the vertical pipes that bring the water from the deep tunnel up to the street-level mains—weren't finished.
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It was basically a multibillion-dollar dry hole for a while.
In 2013, Mayor Michael Bloomberg famously stood 600 feet underground to open the valves for the Manhattan section of Stage 2. It was a huge moment. It meant that for the first time, Manhattan had a real backup. But even then, the job wasn't done.
Why is it taking so long?
People always ask why we can build a 100-story skyscraper in three years but can't finish a tunnel in fifty.
Money is the obvious answer. The budget for New York City Water Tunnel No. 3 is somewhere north of $5 billion, and that number keeps climbing. When the city hits a recession, tunnel funding is often the first thing to get slashed because, well, people can't see the tunnel. It’s easy to ignore a hole in the ground when you’re trying to balance a budget.
But it’s also about complexity. You’re navigating a subterranean obstacle course. Below the streets of New York, it’s a mess of subway lines, gas pipes, steam tunnels, and fiber optic cables. Every time you sink a shaft to connect the deep tunnel to the surface, you’re performing surgery on the city’s nervous system.
There's also the "shaft" problem. To get the water from 600 feet up to the surface, you need these massive distribution chambers. Building those in the middle of a dense neighborhood like the Upper West Side or Chelsea is a logistical nightmare. You have to deal with noise complaints, traffic, and the sheer physics of moving thousands of tons of dirt out of a small hole in a busy street.
The remaining pieces of the puzzle
So, where are we now?
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Stage 3 and Stage 4 are the "future" parts of the plan. Stage 3 involves a tunnel out to the Kensico Reservoir in Westchester. Stage 4 would go through the eastern parts of the Bronx and Queens.
The reality? These stages are often stuck in "planning" or "long-term" phases. The city’s focus right now is primarily on completing all the shafts for Stage 2 and ensuring the connection points are robust enough to allow for the eventual shutdown of Tunnel No. 1.
Is the water actually better?
There’s a bit of a myth that the new tunnel will make the water taste better. Honestly, New York’s water is already some of the best in the world. It’s often called the "Champagne of tap water." Most of it comes from the Catskill and Delaware watersheds, and it’s so clean that it doesn't even need to be filtered (though it is treated with UV and chlorine).
Tunnel No. 3 won't necessarily change the taste. What it will do is improve the pressure. If you’ve ever been on the 20th floor of an old building and the shower felt like a weak leak, the new tunnel and its modern shafts are designed to help fix that. It allows the DEP (Department of Environmental Protection) to manage flow much more efficiently.
What happens if we never finish?
We have to finish. There isn't really a "plan B."
The infrastructure we currently rely on is aging at a rate that should make every New Yorker a little nervous. If we don’t get Tunnel 3 fully operational—meaning every shaft is connected and every valve is tested—we are essentially playing Russian Roulette with the city's water supply.
Imagine a week in New York without water. No toilets flushing in high-rises. No fire hydrants. No drinking water. The city would become uninhabitable in about 48 hours. That is the stake. That is why the Sandhogs are still down there, even when the headlines have moved on to other things.
Actionable steps for the curious
If you want to understand the scale of New York City Water Tunnel No. 3, you can't go down there (it's heavily restricted for security reasons), but you can see its impact.
- Check the DEP Shaft Sites: If you see a weird, permanent-looking construction site with high fences and DEP logos in Manhattan or Brooklyn, look at the signage. Many of these are the "Shafts" for Tunnel 3. They are the only surface-level evidence of the massive project below.
- Track the Capital Budget: For the real policy nerds, the NYC Independent Budget Office (IBO) releases reports on the DEP’s progress. It’s the best way to see if Stage 3 and 4 are getting funded or if they’re being pushed back another decade.
- Appreciate the Tap: Next time you turn on a faucet in NYC, remember that the water traveled over 100 miles by gravity alone and dropped 600 feet into a hand-carved rock tunnel just to reach your glass.
- Support Infrastructure Funding: Infrastructure isn't sexy until it breaks. Staying informed about local bond acts and environmental funding is the only way these multi-generational projects actually get across the finish line.
The story of the tunnel is really the story of New York itself: ambitious, incredibly expensive, slightly dangerous, and hidden behind a lot of grit and concrete. It’s a miracle we’ve built as much as we have, and it’ll be an even bigger one when the last shaft is finally capped and the water starts flowing through every inch of the system.