Seven members of a family from Simhachalam area of Visakhpatnam, had come to visit Tatipudi reservoir, Gantyada Sub-Inspector Tirupati Rao said.
Five members of the family entered into the reservoir to take a bath. K Manisha Gayatri (20) drowned. Her brother K Ashok Kumar (22) also drowned while trying to save her, the Sub-Inspector said, adding their sister G Dharani (24) tried to save the duo but she also drowned.
Their bodies were fished out from the reservoir and sent for autopsy. A case has been registered and investigation is underway, police said.