On 14 Aug 2018 19:27:35 GMT, dpb wrote:

Well, there was one short chunk of PVC at the pressure tank, who knows
what's been done elsewhere...

Good point that there is PVC all over ... which there is. All over.

For example, the four-inch pipe coming out of the storage tanks is PVC,
which means that the steel input you see is actually screwed into PVC.

Same thing on the output, where the pipes in the ground leading to the
house directly outside the booster pump shed appear to be PVC.

I actually got around 75 volts or so to the pipes, as I looked at my
pictures before deleting them from the phone.

But your response explains what we're seeing, which is all that matters,
which is understanding what is.