Exploring Storm Drains: Learning 6 Common Dangers In 2023

Whether you are a beginner, intermediate or experienced urbex adventurer, few things are as enticing to us as the catacombs beneath the city streets, the storm drain system. Since the early days of the building of Paris, France, we have discovered that piping all our undesirable fluids such as waste, sewer, and storm runoff, underground keeps our city streets cleaner and free from flooding.

As we’ve grown larger cities, and developed better modular technology, the age old sewer system has turned into an underground complex maze of corridors and tunnels. As they often require maintenance and inspection, they are built large enough for municipal workers to gain access and roam freely in the concrete tunnels.

If the tunnels are large and open enough for maintenance workers, they are large enough for exploring and investigating by daring and curious urbex wanderers as well. However, exploring storm drains has a different set of variables you may encounter than when you are exploring the abandoned buildings topside.

The tunnels can be enticing but they can be dangerous. There are a few extra dangers common when exploring storm drains that you need to remain aware of and take under advisement before journeying underground into the great tunnel system of your city’s infrastructure.

Looking for additional resources relating to finding and exploring abandoned buildings? Here are some great options:

Difficult Access and Egress

In addition to the usual cautions we take upon embarking on our urbex journeys, exploring storm drains require us to take on a bit more concern and responsibility than the normal concerns about trespassing into an abandoned structure. Storm drains are active and important pieces of your city’s infrastructure and they don’t want anyone vandalizing it so there are likely going to be secure access points and regular maintenance checks.

As a responsible and conscientious urban explorer, take care to respect the local authorities by way of securing their gates, lids and covers back into place once you are finished with your exploration. If you leave them open it only invites troubles and further scrutiny from the authorities. A good urbex steward should leave the site pristine for the next explorer that follows behind them.

Bent bars, loose gratings, unlocked gates, busted doors and abandoned scuttle holes are common access points for entry into the storm drain system and are often found behind overgrown brush, forgotten or deemed to be “too much trouble” by the maintenance workers. Freely roaming the corridors from these access points is nearly identical to how we access above ground structures. But exploring storm drains brings us in contact with the manhole cover.

There is a long list of “why” manhole covers are round including ease of manufacture, ease of transportation, and surface area costs… but the reason the urbex community is most familiar with is because a round manhole cover can not fall down into the round shaft it covers.

This is of critical importance as these things can weight a tremendous amount, often over 300 pounds, and will crush you if handled improperly. Because they keep the above ground world safe from falling into the storm sewers, we should never pry open a manhole for access as it creates a hazard while open.

And they should never be relied upon for an exit strategy either as some may be locked from the topside creating an inescapable tunnel from which you’ll have to turn around and find another exit.

However, if you do find yourself attempting to open a manhole in an emergency situation, caution must be observed. Many of these manholes are located in the middle of active roads and you could be emerging into live traffic. Pushing these extremely heavy and dense objects can be a daunting task while perched precariously on the tunnel’s ladder and the underside of these manhole covers accumulate dirt, grease and oil from the traffic above.

If you are successful in dislodging the cover, slide it to one side being sure to keep your fingers clear of being crushed. Sliding rather than lifting will prevent the dangerous but macabre, cartoonishly comical scenario of the lid pivoting in place and swinging back to hit you. Avoid manhole covers, and use extreme caution if them are unavoidable.

High Voltage Hazards

Getting into and out of these tunnel shafts may require some special maneuvering. It can get quite crowded down there and exploring storm drains may not be a contortionist’s nightmare, but it can call for some creative climbing. Unfortunately, some of that climbing will be on some unsafe structures and dangerous high voltage power lines.

Large cities use their storm drain corridors to run some of their other utilities from building to building. Running power and communication cables underground makes them less susceptible to storm damage and cleans up the skyline just a bit. These dark and damp shafts lie underground, forgotten and unseen by most of the citizens that use their services. Physically, these cable can sit untouched for decades.

This long term exposure to the damp underground atmosphere makes the brackets and frames they are mounted on a prime candidate for rust and corrosion. When the next unwary workman or urbex seeker uses these large cables as a step ladder, the decaying frame may give way causing you to slip and fall. Or worse, become buried and trapped under these large bundles of mammoth cables.

In addition to the physical dangers, underground lines pose the additional risk of electrocution. Many of the outside-plant cables you see run in the storm drains will be copper telephone lines, fiber optic high speed internet cables, and old abandoned signal cabling. Unless you have experience in those fields, you probably won’t be able to tell the difference between these “safe” cables and the potentially fatal electrical lines.

The protective insulating outer jacket on these lines can become frayed through repeated contact, brittle through constant UV light exposure, fatigued by regular impact and contact, or just rendered inefficient due to age and exposure.

High voltage electricity doesn’t care about how it lost its outer jacket, all it wants is the path of least resistance to ground and if you’re exploring the wet storm drains and happen to touch an exposed live wire, you could be seriously injured through electrocution or even cause an explosion.

Fumes and Gasses While Exploring Storm Drains

You may think I’m speaking hyperbolically when I say explosion, but it has been known to happen and can even be considered quite common according to some utility workmen. Exploring storm drains must be done with the complete resolution that you will be coming into contact with gas buildup and possibly toxic fumes so never go in without your respirator.

Gas build up can be due to the density of the gasses themselves. If they are denser than air but less dense than water (for instance your standard gas grill bottle of liquid propane) the gas will sink to the bottom of the drain but stay on top of the water.

If confined, it can build up over time and sit there waiting for a source of ignition. That slight spark of the exposed electrical cable, the errant lighting of a cigarette, or the misguided light source of an exposed flame. Any of these can set off a large explosion capable and documented of blowing open those 300 pound manhole lids.

If you’re down there when this happens, you face not only the flame and concussion of the explosion itself, but also the evacuation of the breathable oxygen during the episode.

Even if the gasses you encounter aren’t flammable, they can cause a serious health hazard to the unmasked urbex. Toxic fumes emanate from the sitting filth and rot that collects underground in the storm drains. You won’t always know when you are breathing in this hazard either.

Some poisonous gasses are invisible, have no scent, or can be masked by other scents, and you are in a confined area breathing the air unable to quickly escape to a clean source of fresh air. Flammable and poisonous fumes are a common risk that you must consider when exploring storm drains. Large city sewers or small town drains, all underground storm drains should be considered contaminated by dangerous fumes.

Biohazardous Wastes

Those gasses and fumes collect in the storm drains because they are the lowest point in the city infrastructure, but also because that’s where we directed them to go. Think about what kind of structure you are exploring. The storm drain or sewer system is where we put all manner of substances we’d rather not deal with on the surface of our city streets. When you explore storm drains, it is is a very real possibility that you come into contact with biohazardous waste material.

What goes down the drain ends up at your feet when you explore the storm drain system. If you’ve ever pulled apart the “S Trap” under your bathroom sink to clean out a clog, you know is can be a disgusting, murky, slimy mess. And that’s just your sink, consider the shower drain, or the toilet.

We flush down all sorts of ick that we want to believe magically disappears but it goes somewhere and as the intrepid urbex explorer, we’ve encountered it once again. So consider the times you have flushed human waste, blood, medicines, etc down the drain… and how much everyone else puts down their drains as well.

Then add in all the material washed down from the street drains such as rubber, oil, littered garbage, cigarette butts… All this mixes together and congeals into a messy and biohazardous wasteland that we consider fascinating because it’s hidden, underground, unseen, and quite frankly, fun.

So when exploring storm drains, be sure to wear protective clothing, cover any open wounds, keep an eye out for fresh wounds that may be incurred during your urbex trip, and wash yourself and your gear thoroughly after exploring. You don’t want to carry disease and illness with you from one excursion to the next by allowing your unwashed gear to contaminate your next adventure.

Drowning While Exploring Storm Drains

What are we exploring? Storm drains.

What is the purpose of a storm drain? To take in excessive volumes of water.

Can we breathe water? No we can not…

All this may seem rather rudimentary, but it bears repeating; when exploring storm drains, drowning is not out of the realm of possibility. Standing water can be deceptively deep, and the influx of surge water from a topside storm can lead to a dangerous flash flood.

We build storm sewers with the idea that in the event of a heavy rain storm we’ll need a place to shunt all that rapidly accumulating water off of our streets and sidewalks. We install these underground corridors and put large drain holes along our streets so the surge of rain water goes underground and out of our way.

Flash flooding is no joke and can be a danger in open fields, and even more so when in a confined restrictive area such as a storm drain. Be aware of the weather forecast and don’t venture into exploring storm drains when there is a rain even imminent. Nobody is immune, not even draining pioneer Rebecca Bunting.

Even a small bit of rain concentrated into an isolated area can flood a single sewer chasm. If you find yourself in that area, the chamber can fill to the top leaving you no room to breathe. And even if it doesn’t fill all the way to the top, those toxic gasses we spoke about earlier can float on top of the rising water leaving you nothing but poisonous gas to breathe.

Swimming out of these water filled chambers may appear easy when we do in in video games, but in real life it’s a lot harder to keep alive when fighting rising waters. The adrenaline rush, the vertigo of the sudden change in orientation, the coldness of the water, the sudden loss of light, bulky or water soaked clothing… all of these factors can result in a watery demise if you get caught in a flash flood.

Becoming a Permanent Resident

Assuming you manage to navigate your way safely into the storm sewer’s entrance, avoid the damaged power line waiting to zap you, use a respirator to keep from breathing poisonous vapors, wear long sleeves to avoid infectious disease, and only explore the storm sewer during the dry season… assuming all of that, you still have to make sure you don’t get lost, turned around, or otherwise find yourself down there longer than you expected.

Getting lost in a storm drain may sound ridiculous to some of you who have only had the opportunity to urbex your town’s minuscule few drain pipes, or if you live in low lying areas, simple culvert ditches. But if you live in a large metropolitan city that has an extensive sewer system, these things can become literal catacombs of adjoining corridors; all of which look similar, and it is easier that you’d believe to become lost.

One concrete chamber is hard to tell from the next and you may be tempted to “remember” your way thinking you’ll only be going down a few feet at turning back. But then something catches your eye and draws you further in. You turn a few corners, jig down one hallway or another and before long, you can’t remember where you came in.

You search for the exit, ANY exit, but find all the hatches locked and properly secured. It could take you some time to manage a way out, in the mean time, your batteries run low, your fresh water and food supply is empty, the gasses accumulate and your trail of breadcrumbs has floated away with the rising water.

Don’t panic. Panic never helps and will cost you nothing but time and resolve. Luckily you never urbex alone or you have someone who knows where you are and what time to expect you back. As you explore storm drains it is wise to bring along clearly identifiable flag ties you can mark your way and retrieve on the way out. Getting lost in the storm drain can be frightening when it happens, avoid it by mapping your system as you go.