Very low likelihood the water would come back.

What they do is sink closed circuits of piping, then run water through them for heating, which is geothermal, not hydrothermal. But that's expensive and depends on the depth to hot crust. In a thin spot, it's easy! Iceland's electricity is very cheap due to this. But somewhere the crust is really thick, like the center of a tectonic plate, it's a long way down. And, with long pipes, there's more risk of them being damaged if there's any geologic activity.