Several hospitals in the city had requisitioned water tanks and residents of apartments and standalone buildings ensured there was adequate water for a day in their reservoirs as the Calcutta Municipal Corporation (CMC) stopped water supply on Saturday morning to fix a breach in a pipe from the Tallah tank to Auckland Square booster pumping station.

Civic engineers said the water supply had to be stopped to empty an underground pit where engineers and technicians had to enter to repair the leak, which occurred in a portion of the pipe located 25 ft below the surface.

By late on Saturday, the leak in the transmission line had been fixed. Engineers of the CMC said water supply would resume from Sunday.

“The breach occurred in a water pipe from the Tallah tank to Auckland Square booster pumping station near Park Street. We had to empty the line between the two places to ensure that water did not flow back into the pit from either ends,” said a civic engineer.

He said the pipe was located 25 ft below surface at the point of the breach, while the same pipe had moved upwards and ran about 5 ft below the ground on its two sides. “If we did not empty the line, water would have flown back into the pit and repairs would not have been possible,” said one engineer.

Civic sources said they had received multiple requests to supply water tankers to hospitals and residential apartments.

Pradip Tondon, the chief executive officer of Belle Vue Clinic, said they had sent requisitions for 50 water tankers, each with a capacity of 3,000 litre. “We have requested for 50 tankers to meet our requirements,” Tondon said.

A resident of a housing complex in Paikpara with 174 families said they had booked for six tankers for Sunday morning. “...This was done to pre-empt any delay in the repairs,” said the resident.

A CMC engineer said, “We had to ensure there was no water in the line for a 5km stretch between Tallah and Auckland Square booster pumping station. The location of the breach is a road next to the railway tracks near Tallah railway station.”

Water supply to the entire north and central Calcutta, portions of south Calcutta and Salt Lake had been cut off for the rest of Saturday after 9.30am to repair the leak.

CMC engineers said it took about one-and-a-half hours to empty the line between Tallah and Auckland Square after water supply water stopped, before engineers could go down into the pit and inspect the breach.

A senior engineer said the leak had been observed many months before but they could not spot the exact location of the leak.

“We noticed wet roads. We could assume there was leak but was not sure of its location till the time water gushed out on the road from below,” said an engineer.