I have seen, on occasion, folks on this site whose situation would call for the use of some flavor of trenchless technology -- this guy is the most obvious example, but others have come up.

However, it seems that directional drilling requires a skilled drill operator to run the machine, and pipejacking may not be possible for DIY-sized pipes, just culvert-sized ones. Is moleing the only option for a DIY trenchless job, assuming your local tool rental place carries a mole and a suitable air compressor? Or does moleing require a similar level of training and skill as directional boring or pipejacking would?

(Of course, you call One-Call and get all the utilities marked out thoroughly, but you'd be doing the same if you were digging a trench, so that point isn't an issue.)


Just got done water driving a 10 foot 1 1/4 inch galvanized pipe through 8 feet of clay, under a sidewalk. We are using it as a casing to run 1" PEX. We put a T on one end of the galvanized with a water hose fitting on one leg of the T, and a cap on the other cross leg of the T. With the water running and a transfer pump to empty the ditch on the side we were pounding from, we drove the open end in, with gentle hits from a 10 lb. sledge on the T and cap end. Worked great, but the cap gave out 6 feet through and needed replacing. Small run, but it got it done.


Thought about making your own? PVC conduit run from an excavation deep enough to go under to another hole deep enough to retrieve. Attach fittings to allow you to use water pressure through the conduit itself to hydraulically bore the hole? Then blow the water out with air, attach fittings, and fish your wire. I have done this for both conduit and water pipes (albeit never 30' across).

You could glue pipe pieces as you go to facilitate ease of insertion and operation. Think male threaded adapter with adapter to water hose thread (or fire hose thread, on a grand scale), as pipe proceeds you cut off and glue the next section, reusing your fittings each time.

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    It gets messy and muddy, for a job like that you might need a ditch pump to get rid of water while you work. Nov 7 '15 at 2:45
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    How do you drive it forward against friction? Mallet? Screw or hrdraulic jack (backed up somehow)? Other?
    – keshlam
    Nov 7 '15 at 3:33
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    I have done this type of PVC drilling myself. Works great under side walks, reasonable sized driveways etc. As a matter of fact one time I decided to bore a hole straight down into the ground just to see how well that worked. Using home water pressure, which was somewhere between 70 and 80 PSI in the area where I lived, I was able to go down about 20 feet. At that depth the water was unable to continue to push the dirt back up along side the 1" PVC pipe.
    – Michael Karas
    Nov 7 '15 at 11:50
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    Note that when boring in this manner be prepared to make a huge mess and be aware that the entry hole size will get progressively bigger the farther you go. This is due to the continued erosion of the hole as the return water and liquefied soil come back out as the boring process proceeds. Another caution I'll point out is that it is better to bore through the native dirt a good ways below the driveway or sidewalk than to be going through the gravel fill that is often put just under the asphalt or concrete. There is less chance of disturbing the integrity of the driveway or sidewalk.
    – Michael Karas
    Nov 7 '15 at 12:00
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    My experience is that this process also works a lot better through clay type soil than through sand or gravel. Sand and the small rocks in the gravel so not liquefy the same as the clay soil does. On the other hand this is where all the mess comes from!
    – Michael Karas
    Nov 7 '15 at 12:03

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