Using a water drill to install PVC pipe in ground

The Engineering Web

Putting a pipe in the ground the easy way using water.

At last it is time to start installing the first part of the antenna... the foundation ground pipe.

Metal pipe is a fine choice for a vertical antenna mount. Since the conductive vertical radiator will be attached to this ground pipe, thought must be given to maintain electrical isolation between the two. Methods include using insulated plastic blocks between the two shafts with non-conductive bolts or straps.

Since this particular antenna will not exceed 17 feet in height and since the option to use rope guy lines exists, I opted to use PVC pipe for the ground mount. This allows:

  • Strap the vertical radiator directly to the pipe
  • Use strong conductive hose clamps to attach the vertical radiator to the ground pipe

Is PVC strong enough to hold the vertical's weight and bending loads?

The highest vertical planned is 17 feet and I do worry about the bending moments in winds. I will monitor the durability of this system over time to see how well this works.

As for the weight of the radiator, the plan is to attach a short length of PVC pipe to the bottom of the vertical so its entire weight will rest on the ground while keeping electrical isolation between the two.

Water Drill

I learned a very good technique from another amateur radio operator for installing ground rods into difficult ground. He used a very simple technique using water.

  • Dig a bowl shaped hole where you want the ground rod
  • Fill it with water
  • Push the ground rod into the dirt
  • Pull the ground rod out and let water enter the hole
  • Push the ground rod further into the hole
  • Do this progressively until your ground rod is at the desired depth while you keep the "bowl" of water full with a garden hose

I used the technique with great success for two new ground rods needed for my electric panel retrofit project. I never used a hammer. Short of hitting a large rock, this technique does not need any hammering.

I wondered if the same technique would work for a PVC pipe. Worth a try...

First prepare a 3 or 4 foot section of 1-1/4" PVC Schedule 40 pipe by cutting one end at an angle to serve as a cutting edge during the "drilling."

Cutting PVC pipe at angle to help installing in dirt.

Water flowing across the holeStart flowing water across the installation site. Take your pipe and just start turning while pressing down into into the dirt. The dirt here in Virginia is hard clay so this takes some effort to do. This is really a core drill as you will see shortly. Be patient and you will have no problem sinking this pipe to any depth you need short of hitting a rock.

Water drilling a PVC pipe into the ground.

An immediate problem was clay plugging the PVC pipe. You will have to remove the pipe every inch or two and push out the dirt clots with a stick or small pipe.

Clots of clay from the water drilling operation removed with a stick pushed through the pipe.

Unlike the simpler installation of ground rods, this pipe did require the use of a hammer to help get through this tough dirt even with the water helping. Just keep repeating these steps:

  • Hammer once
  • Turn 1/4 turn
  • Hammer again
  • Turn 1/4 turn
  • Hammer again
  • Turn 1/4 turn
  • Hammer again
  • Remove pipe and clear the clots
  • Let water fill the hole
  • Sink pipe into the hole
  • Repeat until desired depth is reached

Hammer and twist PVC pipe into the ground with water.

After the pipe reaches the desired depth, you may find the hole large enough to allow the pipe to wobble around. In time, nature will fill the hole with material and capture the pipe securely. For now take some of the clay clots you removed earlier and tap them into the gaps with a stick or small pipe.

Gaps around the PVC pipe.
Gaps around pipe.
Fill the gapsbrwith the clay clots.
Use your drilled
clay "cores"
Adding more dirt around PVC pipe
If you need more
dirt, get some.
Ram the clay clots into the gaps.
Push it all into the
gaps while water runs

At last we have a PVC pipe installed into the ground ready for the next assembly steps.

The PVC Antenna Mount Ground Pipe installed in the ground.


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