Why do pin holes develop in copper pipe and tubing running residential water?

This baffled me for some time, and, after looking into it, I propose the following untested theory.

First, pin holes only develop in cold water lines.

And, only in horizontal running lines.

Vertical lines and hot water lines do not have this problem.

Manufacturers have ruled out defective piping. Many articles rule out acidity of the water.

I have numerous pipes that run horizontally that have never developed a pin hole, yet certain lines develop pin holes on a regular basis.

The difference is the turbidity.

The pipes with a problem have a two way flow-pushed between the pump and pressure tank with water being drawn of from various tees. I propose that the action of hard water full of minerals being swirled by constant back and forth of pressure changes creates eddy pockets where the minerals wear through the pipe over time.

It is easy to fix by placing the pressure pump near the well and using other than copper piping in areas of high turbidity.

John A Sykas