Need a 120 volt sensor

I have a lake house that I rent out and it has a septic system. There is a high water alarm on the control box that truns on a 120 volt light and a piezo siren but it's way out back and hard to see / hear. Am looking for sensor that will alert me if it detects 120 volt power (the light and siren getting power). I'd prefer if it integrated with my Ring Alarm app but honestly will settle for a standalone z-wave device if anyone could identify something like that. Adding cellular monitoring is like $1 for the controller and $20 a month for the servce. I'd be surprised if there's no a voltage sensor or meter that will cheaply do what I've described. Appreciate any pointers!