There will be unscheduled water supply disruption in Petaling, Hulu Langat, Kuala Langat and Sepang, beginning today.

Syarikat Bekalan Air Selangor Sdn Bhd (Syabas) said in a statement today, that the disruption was due to decreased production of treated water by the Sungai Semenyih Water Treatment Plant since 8 am today.

"This happened when the ammonia and manganese content in the river water exceeded the level permitted by the Health Ministry," the statement said.

The Selangor Water Management Authority (Luas) and Syarikat Konsortium ABASS Sdn Bhd are in the process of identifying the cause of the contamination.

Operations at the treatment plant will resume, depending on the contamination level.

Consequently, 39 areas in Petaling, 216 in Hulu Langat, 62 in Kuala Langat and 61 in Sepang are expected to experience water disruption and low water pressure.

Syabas will be supplying water in lorry tankers and static water tanks to the affected areas.