Often when we think of a lightning transient, the idea is that the lightning strikes a power line and propagates through the hot/neutral or 3 wires of 3-phase system. There is also induced current transients.
However, I wonder to what extent lightning can affect the ground system. Most houses where I live are grounded to the water pipe in the house, so I would guess that if the lightning hit say a bridge with a water main on it, it could affect equipment attached to that water line. One article on lightning surges had the paragraph:
Lightning ground current flow results when a strike that discharges to the earth couples into common ground impedance paths, causing voltage differential across the ground grid and between ground-neutral or ground-line circuits. In short, the reference ground (supposedly zero voltage) is elevated a few milliseconds, therefore creating a large voltage difference between ground and the incoming power and/or data lines.
To what extent, if any, does lightning affect ground systems which use water pipes?