PETALING JAYA, Oct 10 — Another week of water disruptions await those in areas affected by the recent shutdown of the water treatment plants in Cheras and Hulu Langat.

Balakong assemblyman Ng Tien Chee said he was informed it would take between five and seven days for pressure to return to normal operating levels.

“The affected area is huge and it will take time for pressure to build up to the level it was before the shutdown,” he said.

“Water would be routed in stages with 25 locations in Kuala Lumpur and 64 in Hulu Langat.”

Ng said the Selangor Water Management Authority (Luas) and Department of Environment (DoE) had failed to properly discharge their duties.

“This coming right after the Semenyih water treatment plant pollution has been resolved is disappointing," he said.

“Agencies and departments responsible for enforcing environmental regulations and maintaining the quality of raw water need to step up their efforts.”

Ng said Luas and DoE needed to review their operating procedures and take swift preventive action when such incidents occurred.

“Monitoring every stretch of river all the time may be difficult. However, there is no excuse not to respond immediately when pollution in a specific area has been identified," Ng said.

“Reliable water supply is of public interest and heads must roll if this happens again.”

Ng also said upstream contamination from Pahang was most likely the cause of the Hulu Langat water treatment plant to cease operations.

He said initial investigations pointed to unspecified contamination from Pahang which found its way to Sungai Langat.

“That river feeds into the Hulu Langat plant and the automatic pollution detection system kicked in and shut down operations," Ng said.

“A team from Luas headed to Bentong to take samples.”

According to Ng, the samples would then be tested and the findings would help authorities determine the source of contamination.

“It is too early to say if we are talking about mining waste or by-products from an industrial plant. Knowing what exactly the contamination is will help narrow down the suspects,” Ng said.

The contamination led to the temporary closure of the Langat and Cheras Batu 11 water treatment plants, affecting some 430,000 households since last Friday.