The Delhi Jal Board (DJB), meanwhile, calls it a “local problem” that affects only a few households — primarily, they say, because of corrosion in service lines carrying the water into the flats from the main DJB pipeline.

Rita Sethi said several flats like hers in Narmada Apartments are getting contaminated water since December. “We initially thought there was a problem with our pipeline or tanks, or even the RO water systems,” she said. “But the quality did not improve even after I got all that repaired.”

A south district DJB official pointed out that only 15 to 20 households complain that they get sewage in their taps. “It can be an individual problem; we are trying to rectify it by digging on hit and trial basis,” the official said.

Sethi said the DJB dug up a portion of the area one week ago but is yet to tap the problem. The authorities have now taken samples of water and sent it to a laboratory for testing. The report is expected soon.

Jal Board’s Chief Engineer B M Dhaul explained: “The service pipes with households mainly take off from the DJB pipes. And these service pipes are rusted or have holes in them nine out of 10 times. That leads to sewage water entering the system. But this problem is very local — the water storage tanks of certain flats may also be dirty, leading to the problem.”

Tehmina Yadav, of flat number 349, said she got her water storage tank cleaned a month ago. “We have made all possible efforts but the problem is with the system (read DJB). The water I get smells of a fish pond.”

Yadav said she has disconnected the pipeline supply from getting into her kitchen. “I can’t take any more chances, especially after my son and mother-in-law, 78, were afflicted with stomach infection.”