Water Resources and Environmental Surveillance (WRES) Department was established in 1995 to provide effective environmental services towards consistent delivery of high quality drinking water.

To this end, since the inception of WRES we have developed our Environmental Surveillance Section (ESS) to provide effective monitoring of the water catchment areas including the rivers and dams with respect to the raw water quality, against any potential pollution sources and activities such as encroachment, and further to make appropriate recommendations for action.

The ESS team is responsible to carry out annual environmental programmes which include regular sanitary surveys, special environmental investigations at water catchment areas, investigations of violations and reporting of raw water pollution to the relevant Authorities i.e. Department of Environment (DOE) and Lembaga Urus Air Selangor (LUAS), and undertaking studies on water quality problems faces by the Water Treatment Plants (WTPs) and Dams.

ESS refers to environmental and water related regulations, namely:
• Environmental Quality Act 1974 (Act 127) & Subsidiary Legislation (Revised 2001)
• Environmental Quality Regulations (Sewage & Industrial Effluent), 1979
• Environmental Quality Regulations (Scheduled Waste), 2005
• LUAS (Selangor Water Management Authrorithy) Enactment 1999.
• Water Services Industry Act (Act 655), 2006*
• Enakmen Pembekalan Air Negeri Selangor
• Irrigation Areas Act, 1953 (Revised 1989)
• Street, Drainage and Building Act, 1974
• National Land Code, 1965
• Drainage Work Act, 1954 (Revised 1988)