The victims, all relatives, had come down to Dindi to attend the 12th day death rituals of a relative and went to the reservoir for sight-seeing and entered the water for swimming.
However, none of them knew swimming and drowned, a police official attached to Dindi police station said.
The bodies of all the five persons were fished out. They were identified as D Jyotsna (20), a BTech degree holder and D Devamani, an intermediate student, both sisters, two brothers D Harshavardhan Reddy (25), a private employee, and Praneeth Reddy (20), a degree student, and their relative Avinash Reddy (25), the official said.