Anna Nagar Residents Seek Independent Probe After Coliform Found in Tap Water

Residents of Anna Nagar have demanded an independent investigation and joint civic inspections after privately commissioned laboratory tests detected coliform bacteria in tap water, following months of foul-smelling drinking water supplies. The Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) has disputed the findings, stating its own subsequent tests found no E. coli contamination.

The issue emerged in the neighbourhood after multiple households experienced a persistent foul odour in their municipal supply. Resident Sudhin Samuel said he first noticed the odour in December 2025 after moving into an apartment in October 2025. Although the residential association cleaned both the underground and overhead storage tanks, the smell remained.

Samuel noted that discussions with neighbours revealed the problem was widespread rather than isolated to a single building. Residents contacted CMWSSB, whose staff inspected properties, tested total dissolved solids (TDS) levels, and suggested line flushing. Because TDS checks do not account for odour, residents arranged an independent laboratory test from a house tap sample, which confirmed coliform bacteria and deemed the water unsuitable for consumption.

The private test results were submitted to CMWSSB on August 2. Following pipeline cleaning, residents were informed that the contamination might be linked to ongoing stormwater drain works and damaged sewerage lines in the area. V. Sandhya of the M. Block Residents Welfare Association emphasised that residents are seeking accountability and coordinated action between the Greater Chennai Corporation (GCC) and CMWSSB to safeguard potable supply networks during civic infrastructure works.

Residents have formally called for independent water testing across multiple points in Anna Nagar, a technical probe into cross-contamination between sewage lines, stormwater drains, and drinking water mains, and immediate repairs to damaged pipes. They have also demanded that all official test results and action reports be made public.

A CMWSSB official disputed the contamination claims, stating that the board's sample tests detected no E. coli and that checks on the supply network found no defects. The official attributed the foul smell to water being stored for prolonged periods in overhead tanks, causing odours when taps are opened in the morning. Residents rejected the explanation, noting that the problem persisted despite tank cleanings, and urged authorities to identify the external source before public health is compromised.