Bulverde runs
on well water.

If you are on a well out here, the water coming out of your sprinklers has been sitting in limestone. Every cycle that hits a window leaves a little of that rock behind. It builds in rings, it goes cloudy, and after a couple of seasons it stops looking like spotting and starts looking like the glass itself has gone bad.

It has not. In most cases it comes off completely. But it needs dissolving rather than wiping, and a hose or a standard clean will do nothing at all. Left long enough it does eventually etch the pane permanently, which is the honest reason not to keep putting it off.