Police in Ban Pao area of Kaset Sombun district had learned about three corpses lying at the bottom of the well earlier in the evening and contacted rescue staff to pull the bodies out.
The drowned persons were identified as Boonterm Buathong, 56, and his sons Chareonchat, 29, and Preecha, 26.
According to Thong-in, 56, her husband and sons had gone to the well on Monday morning to repair it and did not return for lunch. She later found their bodies at the bottom of the well.
The well, located in their farm, is one metre wide and 13m deep. Rescue staff had to wear breathing apparatus to dive to the bottom to pull up the bodies.