: Councillors complained about faecal contamination of drinking water and the rising public health risk in Greater Chennai Corporation (GCC) zones, at the Council meeting on Friday.Valasaravakkam Ward Committee Chairperson V. Rajan submitted to Mayor R. Priya a report alleging that 44 informal water samples tested positive for E. coli and were deemed ‘bacteriologically unsatisfactory’.The data revealed that a ward in Nerkundram recorded the highest concentration, with 12 positive samples, constituting 27.3% of the data analysed by experts between May 26, 2026, and August 12, 2026.Nerkundram (four wards), Chinna Nolambur, Alwarthirunagar, and Maduravoyal areas collectively accounted for 68.2% of the positive cases. According to the documents, the contaminated samples were collected from Metrowater, RO water, wells and borewells at various locations. The sources included Ippasi Street, Mandaveli Street, Mookambigai Nagar, Kadambadi Street, Vallalar Street, and Jai Balaji Nagar in Ramapuram.The residual chlorine level — i.e. the amount of chlorine left in the water after treatment to keep it safe from germs during supply — should be maintained at 0.2 parts per million even at the tail ends of the water supply network, i.e. household connections. This effectively controls E. coli, though its effectiveness depends on factors such as free residual chlorine, contact time, and temperature.MDMK councillor S. Jeevan said the public health risk was high in several areas of north Chennai because of water contamination. DMK councillor Parithi Elamsurithi said the sewer network had been damaged in the areas in the vicinity of Metrorail work, including Purasawalkam, leading to public health issues caused by sewage contamination of drinking water.GCC Commissioner G.S. Sameeran said: “We have taken up the issue with the Chennai Metropolitan Water Supply and Sewerage Board, which is taking steps to identify the source of contamination, rectify it, and improve residual chlorination.” Metrowater urged residents to report civic issues pertaining to water contamination through helpline 45674567. It said efforts were under way to provide safe drinking water for all residents. Published - August 29, 2026 01:13 am IST