The major tributaries of the river are the Chand Khali Nadi and Dolukhal. The Chand Khali Nadi flows through the Patiya Plains, and the Dolukhal River drains into the Satkania Plains. Another tributary is the Kumira Khali, which drains into the Kutubdia Channel. There are seven Bangladesh Water Management Board hydrometric stations on this river, which have been recording data since 1965.
The Sangu drains off the waters of Patiya, Satkania, and Banshkhali Upazilas. It has a connection with the Karnafuli River through the Chand Khali River. The Sangu is a shallow river, but it becomes violent during rains and develops rapid currents. It is navigable up to 48.27 kilometres (29.99 mi) from the estuary. The Sangu gas field is located about 50 kilometres (31 mi) southwest of Chittagong and reaches a depth of 10 meters at its mouth.