Water supply to about 1.2 million people in the Klang Valley of Malaysia that was cut off earlier is expected to fully resume by 03:00 p.m. local time on Wednesday.

A spokesperson from Syarikat Bekalan Air Selangor Sdn Bhd ( Syabas), the water supply company in the State of Selangor and the Federal Territories of Kuala Lumpur and Putrjaya in central Peninsula Malaysia, told Xinhua.

According to the spokesman, the water plant closed down on Tuesday midnight is in the process of restoring the normal water level.

Residences will get water supply in stages, depending on their homes' distance from the water plant, said the official, adding that certain districts have had the water supply resumed.

Klang Valley is an area in Malaysia comprising Kuala Lumpur and its suburbs, and adjoining cities and towns in the state of Selangor.

The unscheduled cut of water supply happened after high levels of ammonia was detected in a water treatment plant in the southern part of the Selangor State.

Local media reported that the contamination was traced to the collapse of a retention wall at a sanitary landfill.

Syabas has activated its crisis operation centers to ease problems in the affected areas, including getting tankers to provide water to the residential areas.