CHENNAI: Sewage was not entering the stormwater drain that carries floodwater from an Ambattur neighbourhood to the Puzhal Reservoir, one of the five reservoirs that supplies drinking water to the city, the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) submitted before the Madras High Court.
The submission was made in a counter affidavit in a writ petition filed by advocate VS Suresh of Thendral Nagar in the Ambattur zone of the Greater Chennai Corporation.
Suresh alleged that a stormwater drain laid during 2021–22 to carry rainwater from New Street through Thendral Nagar 3rd and 1st Streets towards Puzhal lake was not functioning properly. The rainwater stagnated during the 2023 and 2024 monsoons, he said, and alleged that sewage had been diverted into the channel.
When the matter came up for hearing on January 5, the High Court had issued notice to the corporation and CMWSSB seeking response.
In its reply, CMWSSB denied the allegations and stated that the underground sewerage system serving Thendral Nagar and nearby areas, comprising 15 streets, has been functioning properly since 2015. The locality generates about 0.95 million litres of sewage per day, which is carried through pumping stations before reaching the Kodungaiyur Sewage Treatment Plant, it said.
The board said samples collected from the SWDs at Thendral Nagar and Sakthi Nagar 1st Street on February 5 showed parameters such as biochemical oxygen demand, chemical oxygen demand, suspended solids, pH and ammonia within the limits prescribed by the Tamil Nadu Pollution Control Board. It also urged the court to dismiss the petition against it, stating that stormwater drains fall under the jurisdiction of the Greater Chennai Corporation.
Earlier, DT Next had reported that the Water Resources Department received complaints about sewage discharge in Ambattur along the Manal Odai drain canal and had taken up the issue with the Greater Chennai Corporation, noting that the source of inflow into Puzhal Lake required further examination.
During proceedings before the Madras High Court in 2025, the department flagged untreated sewage entering major drinking water sources in parts of the Madhavaram zone, adjoining panchayat areas in Tiruvallur district and Ambattur along Puzhal Lake. At the time, the stormwater drain department said there was no lapse in monitoring. Greater Chennai Corporation officials were not reachable for comment.