Disaster Management Center (DMC) spokesperson Pradeep Kodippili in the latest update said the four deaths were reported from Kalutara and Galle.
Heavy rains had caused flash floods in Badulla, Kalutara, Galle and Kegalle, from where thousands of families were evacuated. Dry rations were distributed to them, Xinhua news agency reported.
Kodippili said waters were receding but more rains were expected in many parts of the island on Monday and Tuesday.
Thunder showers are forecast in northern, western and eastern provinces and in Galle, Matara and Kalutara districts, the Met said.
Heavy rains of upto 100 mm was expected in the Eastern, Southern, Central Sabaragamuwa, Uva and Western Provinces, the department added.
On Monday, Sri Lankan President Maithripala Sirisena left for a three-day state visit to Seychelles, his office said here in a statement.
Playing the first game under new coach Ravi Shastri, India decided to go with five bowlers. All-rounder Hardik Pandya is making his Test debut.
Sri Lanka, meanwhile is led by stand-in-skipper Rangana Herath in place of Dinesh Chandimal, who is down with pneumonia.
India: Virat Kohli (Captain), Shikhar Dhawan, Cheteshwar Pujara, Ajinkya Rahane, Ravichandran Ashwin, Ravindra Jadeja, Wriddhiman Saha (WK), Umesh Yadav, Hardik Pandya, Mohammed Shami and Abhinav Mukund.
Sri Lanka: Rangana Herath (Captain), Upul Tharanga, Dimuth Karunaratne, Kusal Mendis, Angelo Mathews, Asela Gunaratne, Niroshan Dickwella (WK), Danushka Gunathilaka, Dilruwan Perera, Lahiru Kumara and Nuwan Pradeep.