Anybody know of a low water sensor for water troughs that works through a smartphone?

My dad has a pasture about 20 miles from his home...checks the cows every other day or so. The Water supply for the cows is from an electric water well.

Every now and then the well pump will act up and not do it's job meaning the water trough doesn't get filled. Haven't had serious consequences when it has happened, but one never knows.

My question is does anyone know of a system that could monitor the water level and send an alarm to a smartphone when the water level drops? It would seem that in this day of technology someone has developed some type of smartphone app system that could be adopted to monitor water trough levels. Just wondering.

Anybody know of a low water sensor for water troughs that works through a smartphone?