The incident occurred when 10 first year engineering students of a private college here had gone to the dam to spend the day.
Three of them were bathing at a banned spot and drowned in the water, police said.
On hearing the screams of their friends, a person present at the place, immediately jumped into the water and tried to rescue them, they added.
However, he also drowned, police said adding some persons on the bank managed to bring them out of the water.
While two students died on the spot, the others were declared brought dead by the government hospital in Pollachi, police said.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)