So why does steam pour from the streets of Manhattan?

Steam at Times Square. Image: Heitere_fahne/Flickr, reused under creative commons.

Picture a streetscape, New York City at night. Even if you’ve never been you probably have a clear picture in mind. Flickering neon bar signs, the subway rattling underfoot, a solitary cop walking his midnight beat – and a backdrop of steam, pouring out of the pavements.

It’s an integral part of our perception of Manhattan. For the opening shot of Taxi Driver, Scorsese chose to show steam rising from a grill. It gives us location and mood – decrepitude, tension, and, to borrow a line from Tom Waits, a feeling “like the whole goddamn town is ready to blow”.

The plumes rising from New York’s manholes are real – but they are not the product of an ancient, broken down sewer system, or a side effect of the subway trains, as one might assume. In fact we are seeing the world’s largest steam heating networks in action.

The first city-wide heating steam networks sprang up across North America in the 1870s. In 1882,  the commercial New York Steam Company completed its own network, covering Manhattan from the Battery right up to 96th Street. Its pipes delivered steam from generator plants, to paying customers the length of the city. 

This steam was used in laundries, to sterilise hospital equipment, and to humidify valuable museum exhibits. Most of all, it was used to keep buildings warm during the harsh -25C winters. 

At its height, the network was used by over 2,500 buildings, among them some of New York’s most famous landmarks: Grand Central Station, the Empire State Building, the Chrysler Building, Rockefeller Center. Each new skyscraper of the gilded age was a testament to the steam service’s efficiency – just plumb in and you’re set. (Some have suggested this ease of use actually contributed to the network’s decline, as lower-level customers got away with illegally tapping the main lines.)

What is really going on under the streets of New York. Image: Con Edison.

Though today it serves only 1,800 buildings the network is still going strong. It’s now owned by the power giant Con Edison, and its scale is still incredible: three thousand vents and manholes pepper a network which comprises 105 miles of piping, taking 11m tonnes of steam around the city. 

But even with an army of workers maintaining the ancient pipes, things have occasionally gone wrong. Since 1987 there have been 12 steam pipe explosions in the city. Two people were killed in 1989; in 2007 an explosion at a busy intersection during rush hour injured 45. Eye witness accounts describe a boiling plume of steam rose as high as the nearby 77-story Chrysler building.

That’s not the only reason more cities haven’t built their own steam heating networks: a system like this can only ever be viable in a big, densely-populated area like Manhattan. The infrastructure of heavily insulated ceramic piping doesn’t come cheap, so must service whole blocks, rather than individual buildings. Similarly the system relies both on a huge centralised boiler system and injections of waste steam from large power plants located close by. None of this is easy to replicate in a city that already exists.

Incidentally, the stuff we see rising from manholes isn’t steam from inside the system at all. On cold, wet nights, rain and other condensation enters the ventilation system where it comes into contact with the hot pipes. The result is perfectly harmless plumes of water vapour, pouring up from the streets.


CityMetric is now City Monitor! Come see us at our new home

City Monitor is now live in beta at

CityMetric is now City Monitor, a name that reflects both a ramping up of our ambitions as well as our membership in a network of like-minded publications from New Statesman Media Group. Our new site is now live in beta, so please visit us there going forward. Here’s what CityMetric readers should know about this exciting transition.  

Regular CityMetric readers may have already noticed a few changes around here since the spring. CityMetric’s beloved founding editor, Jonn Elledge, has moved on to some new adventures, and a new team has formed to take the site into the future. It’s led by yours truly – I’m Sommer Mathis, the editor-in-chief of City Monitor. Hello!

My background includes having served as the founding editor of CityLab, editor-in-chief of Atlas Obscura, and editor-in-chief of DCist, a local news publication in the District of Columbia. I’ve been reporting on and writing about cities in one way or another for the past 15 years. To me, there is no more important story in the world right now than how cities are changing and adapting to an increasingly challenging global landscape. The majority of the world’s population lives in cities, and if we’re ever going to be able to tackle the most pressing issues currently facing our planet – the climate emergency, rising inequality, the Covid-19 pandemic ­­­– cities are going to have to lead the way.

That’s why City Monitor is now a global publication dedicated to the future of cities everywhere – not just in the UK (nor for that matter just in the US, where I live). Our mission is to help our readers, many of whom are in leadership positions around the globe, navigate how cities are changing and discover what’s next in the world of urban policy. We’ll do that through original reporting, expert opinion and most crucially, a data-driven approach that emphasises evidence and rigorous analysis. We want to arm local decision-makers and those they work in concert with – whether that’s elected officials, bureaucratic leaders, policy advocates, neighbourhood activists, academics and researchers, entrepreneurs, or plain-old engaged citizens – with real insights and potential answers to tough problems. Subjects we cover include transportation, infrastructure, housing, urban design, public safety, the environment, the economy, and much more.

The City Monitor team is made up of some of the most experienced urban policy journalists in the world. Our managing editor is Adam Sneed, also a CityLab alum where he served as a senior associate editor. Before that he was a technology reporter at Politico. Allison Arieff is City Monitor’s senior editor. She was previously editorial director of the urban planning and policy think tank SPUR, as well as a contributing columnist for The New York Times. Staff writer Jake Blumgart most recently covered development, housing and politics for WHYY, the local public radio station in Philadelphia. And our data reporter is Alexandra Kanik, whose previous roles include data reporting for Louisville Public Media in Kentucky and PublicSource in Pittsburgh, Pennsylvania.

Our team will continue to grow in the coming weeks, and we’ll also be collaborating closely with our editorial colleagues across New Statesman Media Group. In fact, we’re launching a whole network of new publications, covering topics such as the clean energy transition, foreign direct investment, technology, banks and more. Many of these sectors will frequently overlap with our cities coverage, and a key part of our plan is make the most of the expertise that all of these newsrooms combined will bring to bear on our journalism.

Please visit going forward, where you can also sign up for our free email newsletter.

As for CityMetric, some of its archives have already been moved over to the new website, and the rest will follow not long after. If you’re looking for a favourite piece from CityMetric’s past, for a time you’ll still be able to find it here, but before long the whole archive will move over to City Monitor.

On behalf of the City Monitor team, I’m thrilled to invite you to come along for the ride at our new digs. You can follow City Monitor on LinkedIn and on Twitter. If you’re interested in learning more about the potential for a commercial partnership with City Monitor, please get in touch with our director of partnerships, Joe Maughan.

I want to thank and congratulate Jonn Elledge on a brilliant run. Everything we do from here on out will be building on the legacy of his work, and the community that he built here at CityMetric. Cheers, Jonn!

To our readers, on behalf of the City Monitor team, thank you from all of us for being such loyal CityMetric fans. We couldn’t have done any of this without you.

Sommer Mathis is editor-in-chief of City Monitor.