The Selangor Environment, Green Technology and Consumer Affairs Committee chairman said the source of the pollution is suspected to have come from the Nilai 3 Industrial Zone and a goose and duck farm situated on the banks of Sungai Batang Benar and Sungai Pajam.
"Both of these suspected sources of pollution are situated in Negri Sembilan. We could not detect any sources from within Selangor.
"From the farm, until 9am yesterday, there was a big cleaning up at the coops which washed out to the rivers.
"We have yet to pinpoint exactly but these are the suspected places," said Hee on Monday (Oct 5).
He also said that the Sungai Semenyih and Bukit Tampoi water treatment plants would only resume operations after the odour had been removed.
"For now, we are trying to dilute further the water from Sungai Semenyih," said Hee at the press conference which was also attended by representatives from the Selangor Water Management Authority (LUAS) and Selangor Department of Environment (JAS).
He said that action will be taken against the perpetrators once the source has been identified.
On Sunday (Oct 4) night, Air Selangor announced a water cut to 309,687 Air Selangor account users in the Klang Valley.
The Sungai Semenyih and Bukit Tampoi water treatment plants had to completely stop operating following pollution detected in Sungai Semenyih, which is the raw water source for these plants.
The incident comes just one month after the odour pollution in Sungai Gong which led to water disruption that affected 1,292 areas in the Klang Valley and nearly 1.2 million consumer accounts.