Water Quality Monitoring Map

In response to Member Countries’ concerns over potential water pollution and its trans-boundary implication, in 1985 MRC began a water quality monitoring programme in Lao PDR, Thailand and Viet Nam. Cambodia joined the programme in 1993. The current Water Quality Monitoring Network includes water quality monitoring at 48 permanent monitoring stations; of which 11 are in Lao PDR, 8 in Thailand, 19 in Cambodia and 10 in Viet Nam. Samples of surface water are taken from the river mid-stream every two months, i.e. six times a year starting from February. Member Countries may increase the sampling frequency, but this is not more 12 times a year. Water quality analysis is conducted in designated laboratories.

Based on a review of the scientific literature and a statistical analysis of the MRC data, a Water Quality Index has been designed based on a set of key water quality parameters. The Water Quality Index shows the pressure exerted by human activities on the water quality of the Mekong River. The Water Quality Index is calculated each year for 17 stations in the mainstream of the Mekong River from the Northern Lao PDR to the Mekong Delta.


 - Class A - No Impact

 - Class B - Slight Impact

 - Class C - Impact

 - Class D - Severe Impact

The map contains a marker at the location of the Water Quality Index monitoring stations, and the colour of the marker is based on the Water Quality Index class for 2008,

Click on a marker for more information on the station and to review the Water Quality Index class from 2000 to 2008.