In the "How to drive the ground rods in" thread, Ralph Mowery wrote:

Dig out a hole about 4 or 5 inches in diameter and about that deep.
Fill it with water. Put the ground rod in the center of that hole and
push it down. Then pull it back slightly. Doing this several times you
should be able to get to get it down several inches with each cycle.
Keep doing this without stopping. If you get to about 3 or 4 feet put
the rod all the way out and fill the hole with water . Put the rod back
in the same hole and keep pushing and pulling it a few inches at a
time.

Good evening, Ralph.

That brought something else to mind... something I'm sure has been thought
of by greater minds than mine, and one or two of you have hinted at
something like it in these last few threads...

How about a 10-foot length of copper water pipe, connected to a garden
hose with an adapter fitting (as simple as a short length of another
garden hose, clamped to the pipe with radiator hose clamps). Run water
down the pipe and stick the pipe in the ground, pulling it up and pushing
it down so that the water helps drill the hole in a manner just like you
described. Keep it up until it has gone in as far as it will go, then (if
it hasn't gone in the whole 10 feet) cut it off and solder a copper cap on
the end.

You end up with a hollow pipe in the ground instead of a solid steel rod,
but everything I read about lightning strikes says that the vast majority
of the current flows in skin effect anyway.

I did something like this once in my backyard when I was about 9
years old, using our garden hose. I recall being amazed at how the hose
just kept going in, kept going in ... 'course then when I tried to pull it
out again it was a different story. My father was not happy. :-(

If a hollow water pipe isn't a good enough ground rod, how about drilling
the hole as described above using the water pipe, and then (if I can get
the pipe back out of the ground) beating the ground rod into the resulting
hole? Should go in pretty easy...

I know that by now everyone pretty much believes that a house's copper
water pipes don't make good grounds, but that's mostly because they aren't
connected very well to actual ground... in my house, the copper water
pipes go to the water pump which sucks the water out of the well via a
hard rubber hose... not very good for ground. The only connection to
ground we got (before I connected the copper pipes to the service ground)
was through the minerals in the water.