How Do You Steer a Drill Below The Earth?

How Do You Steer a Drill Below The Earth?

When the commotion of construction must be minimized, try horizontal directional drilling!
📺 Get a year of CuriosityStream AND Nebula for 26% off, just $15/yr!

Watch the Coding Train video:
Play the simulator:

Like laparoscopic surgery for the earth, horizontal directional drilling (or HDD) doesn’t require digging open a large area like a shaft or a bore pit to get started. Instead, the drill can plunge directly into the earth’s surface. From there, horizontal directional drilling is pretty straightforward, but it’s not necessarily straight. In fact, HDD necessarily uses a curved alignment to enter the earth, travel below a roadway or river, and exit at the surface on the other side.

Practical Engineering is a YouTube channel about infrastructure and the human-made world around us. It is hosted, written, and produced by Grady Hillhouse. We have new videos posted regularly, so please subscribe for updates. If you enjoyed the video, hit that ‘like’ button, give us a comment, or watch another of our videos!


Please email my agent at

This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.

Collaboration with Daniel Shiffman (@The Coding Train).
This video is sponsored by CuriosityStream and Nebula.
Stock video and imagery provided by Getty Images, Shutterstock, Pond5, and Videoblocks.
Music by Epidemic Sound:
Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License
Producer/Writer/Host: Grady Hillhouse
Editor/Production Assistant: Wesley Crump
Script Editor: Ralph Crewe
Intern: Myles Jonas

You may also like...

38 Responses

  1. Practical Engineering says:

    📺 Get a year of CuriosityStream AND Nebula for 26% off, just $15!
    🚂 Check out the Coding Train video and play the Horizontal Directional Drilling simulator!

    • WarttHog says:

      Great to see you in Nebula too, Grady!! I’ve signed up because it’s a convenient way to support my favorite creators (of which you are definitely one!), but I still use YouTube for now until the Nebula app matures a bit more.

      Plus I’ve gotten so used to sponsor messages that a video feels like it ends too abruptly without one! Haha.

      Thanks for all you do!

    • ro pro says:

      Interesting! I always wondered how they steered these drills!

    • UstedTubo187 says:

      Love me some Coding Train!!!

    • Repent and believe in Jesus Christ says:

      Repent to Jesus Christ
      “For everything that was written in the past was written to teach us, so that through the endurance taught in the Scriptures and the encouragement they provide we might have hope.”
      ‭‭Romans‬ ‭15:4‬ ‭NIV‬‬

    • Symmetrie Bruch says:

      @Mars Freelander wow O.O don´t tell me you´re actually one of the very few chosen few who posses the gargantuan, unfathomable intellect to actually use an adblocker. i didn´t dream it possible

      it´s literally IN the video mate, if you haven´te watched a sponsored message by a youtuber for 5 years, you haven´te been watching youtube in 5 years

  2. StefanD says:

    Here in Germany that drilling method did become more known to the public when the company “FlowTex” was sued for the (back then) most expensive large-scale fraud in Germany. The damage was roughly 4.2 billion USD.

    The company had 270 machines but those were sold multiple times (3142 machines had been sold).
    When they had investors visiting they drove to one drilling site, then had lunch and then drove to a different drilling site. During the lunch brake they moved the drills from site 1 to site 2 creating the illusion of a bigger pool of machines.

    • Sincerely Yours says:

      @dispatch-indirect You have to catch and prosecute the “brass balls” who pull off scams like that. Admiring them just encourages them to do more damage.

    • dispatch-indirect says:

      You have to admire the brass balls it takes to pull off a scam like that.

  3. hankschannel says:

    Thanks Grady! This answered so many questions that I didn’t even know I had. We had one of these drill right through the water supply to our house. They were like, “there isn’t a pipe here” and I was like, “well, there’s no water going into our house anymore so…”

    They had it all patched up in a couple days.

  4. Dakota Flowers says:

    My hone region of ohio is known as “DD paradise” because there are 50 or so directional drilling companies based in a 20 Sq mile area. Also 4 years ago, TC Energy did a reconstruction project on the east buckeye express 36in diameter natural gas pipeline which travels underneath 3 major waterways in my region. My favorite way to kill time was to go out and watch the semi sized drilling rigs boring and pulling up to 3 miles of pre-bent thick wall pipeline on the ROW.

  5. dcviper985 says:

    I work in the fiber optic network industry, and previously worked in the gas utility industry. We used to joke that you should always carry a length of fiber optic cable with you in case you get stuck on a deserted island. Just bury the cable and when the guy with the backhoe comes out to cut it you can just ride back with him.

    • Josh Liechty says:

      As much as that terribly destructive invasive species, the North American Fiber-Seeking Backhoe, is a pain in the backside, it can come in handy! 😀

    • Demon Raptor says:

      @Jared Waldien love these jokes. I promise a lot of us do try not to disturb markers but mistakes do happen and I do apologize for the ones I’ve accidentally knocked down.

    • Jared Waldien says:

      In surveying we had a similar joke. If lost set a survey marker and someone on a piece of excavating equipment will be by shortly to tear it out.

    • xtranormal23 says:

      Good joke but it’s hard not to blame the guy that put it there using only the sod to cover it.

    • tuck shop says:

      I just laughed out loud at this.

  6. erikig says:

    I drove by these crews in Broward for months and didn’t get what they were up to and why it was taking so long.

    It is so easy to get frustrated with the delays they kept causing 😅, thanks for helping me understand the complexity of what was going on.

  7. Wojtek says:

    I assisted an HDD on Mariner East 2, ME2. We had an inadvertent return so bad we built a pit around it and simply used it as a recirculation pit. There was a lot of effort to mitigate damage professional geologists at each drill and field techs/engineers walking the surface to look for IR’s. Amazing tech

    • Wojtek says:

      @KevinDC5 I just really enjoy nears and my family is polish lol

    • KevinDC5 says:

      My last name is Wojtek. Not often I see that name anywhere.

    • its d0nk says:

      @Wojtek peace of mind*

      And thanks for bringing your story and experience with this, especially as part of the mentioned pipeline in the video. Very interesting stuff.

    • Wojtek says:

      @cody collins The ME was issue prone so it was written into their permits they would have a PG and environmental techs/field engineer/inspector from a third party. It was expensive but helped get issues resolved quickly and give the DEP a piece of mind.

  8. Shefle says:

    I’m honestly impressed by the time and effort you put into these videos, Keep it up!💛

  9. vipahman says:

    That string in the gel demo was awesome and gave such a simple and precise explanation of a problem that I always wondered about. Beautiful!

  10. Saablazer says:

    I work for a water/sewer district and because of our topography, we use a gravity sewer system. This means that all our sewer lines must be perfectly straight and at precise angles. Because of this trenching is preferable as directional drilling is not perfectly straight and this creates low and high spots in the line which will require continual flushing and maintenance. We do occasionally use boring to lay water pipe underground though as it is not requisite that water pipe be perfectly straight.

    • Rob Wenzel says:

      I work for our water department as well and all our sewer lines are all gravity, we don’t have a single lift station

    • Saablazer says:

      @Vic Scott in the video itself, he said that directional drilling isn’t straight. It’s continually curving. Also we have no control over the contractors we use. We have to put projects out to bid and are legally required to choose the lowest bid. The lowest bidder often subcontracts out the work. Using open trenching, we get perfectly straight lines, GPS shots of the pipe in situ for mapping purposes, and we use lasers and other means to keep an exact grade.

    • night hawk says:

      Yep, microtunneling is king for gravity pipes

    • Vic Scott says:

      I would look in to wire line and/or better drillers if you are facing those issues.

    • Михаил Дмитриев says:

      I work for a telecom company and HDD is a godsend sometimes for laying optic cables 💪 Literally zero downsides, except for cost 😅

Leave a Reply

Your email address will not be published.