Actually, the box I have is this one.
There is no well. It pull directly from an irrigation canal (piped) and since the neighborhood system is quite complex and old, there are frequently times when there isn't enough water in the line to run the sprinklers, so the Smart Box cuts power to the pump to avoid burnout.
There is no auto-restart if pressure returns. So the rain delay approach previously suggested would seem to work well. At least it would notify me when the system stopped pumping so I could manually run the system later when there was water. Otherwise Rachio thinks it is watering, I think it is watering, but it isn't and that is no good on any front.