Buried beneath every American city is a mysterious jumble of cables, pipes, and gas lines, entangled like a pair of wired headphones the moment you pull them out of your pocket. Every time a contractor sticks a shovel in the asphalt, they embark on a high-risk excavate-by-dots obstacle course, dodging color-coded clusters of spaghetti-like power lines, gas mains, sewers, and fiber-optic cables. A line of blue spray paint means water. Red means power. Yellow is gas. Orange is telecom. 

About 700,000 times a year — that’s once every 47 seconds — something goes wrong. 

A backhoe slices into a cable and cuts off a 911 call center, or a woman comes home to find her dryer and hot water heater on fire after a contractor pierced her electrical line. Just last week, a contractor accidentally severed a single telecommunication cable that proved critical enough to ground flights at some of the nation’s largest airports on the eve of the UN General Assembly, ensnaring even world leaders like Canadian Prime Minister Mark Carney in delays. 

The ground beneath our city streets has never been so crowded, driven by a furious race to lay fiber optic cables carrying the data that fills your social media feeds and transmits your ChatGPT queries. Nor have the systems we use to find out where it’s safe to dig — namely, a hotline and all that colorful spray paint — ever felt so catastrophically insufficient. 

“If the locator mismarked the line, if the line wasn’t marked, if there was no map that even said the line was there,” said Sarah Magruder Lyle, president of the Common Ground Alliance, a trade association focused on underground damage prevention, “there are a variety of issues that could happen before the excavator even puts a shovel or a backhoe in the ground.”

According to Common Ground, such incidents cost the US about $83.2 billion per year, roughly as much as we invest in public transit annually nationwide. But the actual financial toll may be even higher, because every time a crew stumbles across a mislabeled power line or a gas pipe everyone else forgot about, it can delay construction for months on end. As Magruder Lyle put it, “if they get out there and they find something that they’re not supposed to, you have to go back and reengineer the whole project.” 

Such surprises can also lead to tragedy. A 5-year-old named Alistair Lamb was killed in Missouri last spring after a contractor drilled into a gas line near his home, spewing fumes that leveled his house when his unsuspecting father flipped a light switch. And just this May, another unmarked gas line killed three people when contractors struck it, leading an apartment complex in Dallas to explode.

Yet the messy underbelly of our cities remains largely invisible, with accountability for issues foisted upon and at times evaded by a hodgepodge of finger-pointing private utility companies, agencies, and contractors. And that’s a shame because there is, in fact, a better way to bury the cables and pipelines that our modern lives depend on, and a multitude of better ways that we can find the ones we’ve already buried. 

What Disney World gets right about the stuff we bury

To understand one utopian vision for how all this could work, look no further than the happiest place on Earth. That’s a moniker Disney World has earned, in my mind, not for its Mickey Mouse waffles (though my niece may disagree), but for its world-class utility corridors, also known as utilidors.

Directly beneath the Magic Kingdom is a sprawling network of tunnels. Initially designed to shepherd around Mickey and his friends, the system now also serves as one of the largest utility corridors ever created. Unlike the rest of America, where cables are typically dumped in ditches before being covered with dirt, the electrical lines that power Cinderella’s castle quite literally get the princess treatment. 

Alongside water pipes, sewers, and animatronic control systems, these power lines lace the walls and ceilings of the utilidors, meaning they’re protected from weather and changes in the soil. They are also easy to monitor, catalog, and access if something needs fixing. While the cost of building a controlled system like this is much higher upfront than burying directly in the ground, the practice virtually eliminates the risk of accidentally rupturing a gas main or slicing a fiber optic cable during routine maintenance. Once they’re built, they can also drastically reduce costs in the long run because you no longer need to tear up a street every time a utility needs fixing. 

“Obviously, it’s expensive,” said Debra Laefer, a professor of civil and urban engineering at New York University, “but in the long term, it would be hugely cheaper,” especially “in areas where we are digging all the time, there’s a direct business case for moving towards these utilidors.”

As fantastical as Disney World’s imagineered system may seem — and it was, to be clear, predicated on a not-easily-reproducible master plan — the idea of storing utility lines in easy-to-access tunnels is not just for amusement parks. It is possible even in places where most of those lines are currently lying in the dirt, as Prague proved back in the 1970s, when the city decided it was fed up with destroying its precious cobblestone streets every time a buried pipe or cable needed fixing. The city now boasts a sprawling utility tunnel network, occasionally patrolled, evidently, by a couple of robot dogs tasked with mapping out every cable. 

Singapore has also spent years building out walkable utility corridors that operate much like the Magic Kingdom’s, transmitting water, data, and energy from the safety of well-organized underground tunnels. Some of Tokyo’s largest districts store their cables and gas lines in huge concrete utility ducts, and many Parisian water lines and fiber optics are kept across the city’s centuries-old sewer system, a catacombs of waste made easily navigable by blue-and-white street signs that correspond to the avenues above. Many university campuses across the US also boast their own sprawling utilidors.

In most cases, cities chose not to relocate utilities all at once, a feat that would probably be financially prohibitive and deeply disruptive. Rather, they took advantage of all the times they’ve needed to relocate utility lines anyway, a standard (and expensive) practice for big building projects like the Wallis Annenberg Wildlife Crossing or the Second Avenue Subway, a major transportation project in New York City that’s been consistently delayed by unmapped utility lines. A group of graduate students found that building such a tunnel in parts of NYC would likely cost at least twice as much as dropping a utility line in the ground, but could recoup the costs within 47 years. 

“There are streets in New York City that have been excavated at least once a year, every year for the past 30 years,” Laefer said. If you just prioritize those streets, gathering the piping in a “big concrete box” underground, you could allow workers to complete most repairs without needing to disturb the streets or sidewalks above at all.

But building new utility tunnels would require that we first come to better understand the wires and piping already entangled under our cities, which if you recall, we have only a surprisingly flimsy picture of in most cities today. But if every surprise utility line is an opportunity to move it somewhere better, it is also an opportunity, at the very least, to map out where it is.

To that end, a few years ago, Laefer led a $1.2 million pilot funded by the National Science Foundation to create a test case for 3D-mapping New York City’s underground utilities, a project that’s since been adopted into a citywide initiative. The city says it plans to roll out the spruced up utilities locating system in 2028. The UK debuted a similar digital map of over 3 million kilometers of underground pipes and power, owned by hundreds of utilities and agencies a few years ago. The nation projects that it could help save over $500 million per year by minimizing delays and accidental damage. In places where Singapore has not yet stuffed its utilities into walkable tunnels, the city’s own mapping and utilities coordination has already saved it an estimated $230 million in avoided clashes since 2024. Not bad for an intervention that doesn’t even require any physical rebuilding.

So why hasn’t every American city copied London or Singapore?

Well, US cities tend to be plagued by even more private utilities and patchwork local and state norms and regulations than a nation like the United Kingdom. Getting them to pool together what they often consider proprietary underground data is challenging, and few local officials have opted to prioritize such efforts. But this may well change as more and more fiber optics go into the ground, more flights get canceled, more apartment complexes explode, more power lines flicker off, more sinkholes form, and more Americans come to be all too acquainted with the perils lurking just beneath our feet. 

“I think at this point, it’s more about political will and money than any technical obstacle,” Laefer said. “Technically, we’re there. It’s just a matter of doing it.”

The Soviet Union famously churned out tens of thousands of new apartment buildings in the 1960s, ’70s, and ’80s — some assembled in as little as 12 days — together comprising tens of millions of individual apartments. Such speed is not unique to communist command economies, or even to grim concrete mega-blocks. In Sweden and Japan today, modern, high-quality new homes can be factory-built and assembled in a matter of weeks using the same basic method — prefabrication — as the Soviets.

The US, alas, evinces no such urgency to build housing. 

In some of our highest-cost cities — San Francisco, New York, Miami — it takes, somewhat astonishingly, nearly five years to erect a modestly sized apartment building, from the time an application is first submitted to building completion. That was one of the top-line findings of a remarkable new economics working paper on housing construction timelines across 60 US cities. The gaps between the fastest and slowest cities were just as striking: In Raleigh, North Carolina, a builder can complete a 20-unit apartment building in about as much time as it takes just to approve the permit for one in San Francisco, where applications languish for more than a year. In Indianapolis, a single-family home can be built in six months from proposal to completion, less than one-eighth the time it takes in San Francisco.

Such delays have costs — in delayed housing supply at a time when America is millions of homes in the hole, in lost staff time that developers ultimately bake into the cost of the new homes, and in homes that simply never get built because the process is discouraging to anyone but the best-resourced developers. The authors, Leonardo D’Amico, Evan Soltas, and Audrey Wang, found that longer permitting lengths are correlated with higher housing prices and lower rates of housing production, though they don’t claim to have shown that these are causal relationships. The research (which has not yet been through peer review and, like any working paper, may be revised before final publication) represents the first such comprehensive dataset comparing homebuilding timelines across the US. To build it, the researchers assembled 1.1 million permits covering 2.7 million housing units between 2000 and 2025 — about one in 13 new homes permitted nationally over that period, they write. 

It probably won’t come as a shock to you that housing can be built faster in Sioux Falls, South Dakota, than in Los Angeles or pretty much anywhere in California. But perhaps the most notable takeaway (to me, anyway) from the paper was how massively home permitting times have lengthened across the board over the past 25 years. Across the cities in their sample, the researchers estimate that permitting time for a standardized multifamily building rose from 0.6 years in 2000 to 1.5 years in 2023, and, for a single-family home, from 1.6 months in 2000 to 4.9 months in 2023. 

Is there really any good reason why we should take nearly a year longer to approve an apartment building than, Soltas joked in a recent interview, “the barbarians of 2006”? Shouldn’t we be getting faster and more efficient at building housing over time, not slower — especially at a time of acute housing scarcity? 

You would think. So what is going on here?

One building, very different wait times

Permitting refers to everything that happens after a developer submits an application to build a house or multifamily building, before they’re allowed to break ground. The proposal is then reviewed for compliance with a range of different sets of rules, from building safety and energy codes to plumbing to zoning and, in some places, aesthetic design. Initial applications will often be found noncompliant and then sent back to the builder for revisions, Soltas, an assistant professor of economics at Princeton, told me.  

The gulf between housing starts in California and Texas has become something of a meme in housing abundance circles. But, for all that, we have until now lacked rigorous apples-to-apples comparisons of permitting and building times in different metro areas, Soltas said. That gap in seemingly basic knowledge, what should be “step zero” facts for the national housing reform debate, became apparent to him when he was teaching an urban economics class, which became one of the impetuses for the new paper. “I realized if I needed that information to teach my students, that it might be useful for other people,” he said. 

Rather than merely pulling permits from different cities and comparing how long whatever happened to be built in each city took to approve, the researchers used the data to estimate how long an identical, standardized project would take in each place between 2015 and 2019, keeping constant its size and the density of the surrounding neighborhood. Their uniform archetypes were a 2,800-square-foot detached single-family home on a 0.15-acre lot and a 20-unit multifamily building with 1,200 square feet per apartment.

Cities with longer permitting times also tended to have longer construction periods — the longer it takes to get an application approved, the longer it then takes to do the building itself, which compounds the gap between the fastest- and slowest-building cities (it’s possible that “cities that make the permitting process difficult also put in lots of burdens that slow the construction process,” Soltas said). One advantage of the researchers’ method is that the differences across cities can’t merely be chalked up to something like the complexity of building within already-dense environments like Manhattan — the analysis already controls for that. So the enormous gaps between different places become harder to dismiss as inevitable features of development in big cities.

The study wasn’t designed to answer the “why” of it all — those will be questions for future research. “Our paper doesn’t directly identify any smoking guns,” Soltas said. Still, some of the culprits are likely obvious — California, for example, has long subjected some housing projects to extensive environmental review requirements under the California Environmental Quality Act (CEQA). Apartment buildings, especially larger ones, are more likely to have to go through CEQA review, though they’re more environmentally friendly than single-family homes (recognizing this as an obstacle to housing affordability, California has been moving to exempt many housing projects from such reviews). 

Why are we taking so much longer to permit housing?

But why, as the study finds, is permitting becoming slower across the country, not just in the most regulated cities? “We estimate that, in 2000, our standardized multi-family project had a 71-percent probability of approval within six months of applying for a permit,” the researchers write. “In 2025, that project had a 44-percent approval probability within six months.” Permitting times have come down a bit since 2023, but it’s unclear whether that just represents the reversal of pandemic-era highs, or if it reflects real progress from the pro-housing policies that have been passed in many cities and states in recent years. 

That discovery dovetails with other economics research finding that zoning codes, which were first widely adopted in the US in the early-to-mid 20th century, have continued to become more restrictive even in recent years, making it harder to build housing. 

Without knowing why exactly permitting lengths have ballooned, it’s hard to say whether those increases have occurred for good reasons. At least some of it may have to do with the aforementioned intensification of zoning and other land-use restrictions, which, I can say from having written a lot about zoning, tend to be pretty ill-conceived and hard to justify. 

The slowdown may also be connected to expanding building code requirements. I’ve written at length about that issue, too; although ever-more stringent rules might seem like a great idea — who could be opposed to more safety? — they tend to be biased against multi-family housing and likely inflate the cost of building, all without having to show that the benefits are worth the costs. Particularly the cost in housing supply that never gets built, which has the effect of keeping more Americans living in older housing stock. And do we really think a home built to 2005 standards is dangerously subpar today?  

We might ultimately decide that many of today’s building requirements — particularly ones like stronger energy efficiency standards — are worth it, but first we’d need to determine what their full costs are, which we remain far from doing. 

At a minimum, it seems unlikely that an apartment building that’s okay to build in Grand Rapids today would be unsafe for New York. So what, exactly, is all that extra permitting time buying the city? Now, at least, Mayor Zohran Mamdani can put an exact number on the delay.