In the first incident, two siblings drowned while taking bath in a pond at Fabarahi village, Kusheshwar Asthan police station officer-in-charge Rashid Parvez said.
They have been identified as Suman Kumari (14) and 12-year-old Rahul Paswan, the officer said.
In another incident, two girls drowned in a ditch at Dilwarpur village in the district, police said.
Bodies have been sent for post-mortem, they said.