Langat River, which is a very important source of drinking water, as well as development in the Langat Basin, needs special care to reduce the pollution. Environmental Quality Report of Department of Environment since 1997 to the latest 2013 addressed that the river possessed the status of class III which required extensive treatment before drinking. However, more than one of the nine water treatment plants in the basin had to remain closed several times during 2012-2015 due to high concentration of chemical pollution in the river. Therefore, the review of secondary literature found out the reasons of chemical pollution in Langat River. The hazardous chemical pollution in the river was mainly due to the anthropogenic activities as well as there was lack of enforcement of policies to reduce the pollution. Hence, a proper and up-to-date chemical using guideline is required for the basin in reducing the water pollution which would be applicable for all the basins in Malaysia.