The incident occurred around 3 AM when the car driver lost control over the vehicle while crossing a cause-way and overturned before falling in the river resulting in the death of six persons on the spot, police said.
One person travelling in the car survived the accident, they said.
The victims were on their way to Bhujabala mandal from Eluru, a senior police officer said.
The deceased have not been identified yet and investigations were on.