CEO K Pathmanathan said the rupture was expected, as the pressure lowered when the mains were closed to allow for the valve repairs. The two Swiss-made valves measuring 1.35m had provided 50 years of use.

The failure of the Sungai Perai riverbed pipe caused a sudden water interruption to some 200,000 consumers on Dec 18 and took almost a week to repair.

Pathmanathan said a team of 16 divers were sent to the bottom of the river to carry out another round of repairs.

“When PBAPP shut off the water supply at 3.45am, the drop in water pressure dislodged the clamp we installed on a leaking section of the 1.35m riverbed pipe in December,” he told reporters here.

Pathmanathan said a more secure clamp over a large section of the leaking pipeline was installed, but this was a temporary fix.

He said an S-bend pipe would be constructed as a permanent fix, but that would take time as it requires Putrajaya’s approval.

“We need the irrigation and drainage department’s OK, and that will take five to eight months,” he said.

Separately, Pathmanathan said repairs to two major valves are ongoing and on track to be completed by 6am tomorrow.

He said after this, recovery would begin, with water restored to 33% of customers in Seberang Perai by Friday, 6am. This figure will rise to 84% by Saturday morning, he added, and the remainder by Sunday.

Pathmanathan said 87 water tankers have been deployed throughout the state to assist residents.