Rajeshwari was reportedly in financial trouble and also upset with some family problem for the last few days, they said.
Unable to bear the burden, the woman threw the kids, aged three years and twins aged one and half years, into the tank near her house in K Chettipalayam and then jumped into it.
The neighbours, on hearing the sound, rushed to the spot and took them out. However, the kids had died and the woman was saved and admitted to the government hospital at Tirupur, police said.