Solid waste in developing countries is generally disposed of in uncontrolled open dumps. This solid waste sites can be sources of groundwater contamination. The environmental consequences of such inadequate disposal sites are often obvious, yet necessary improvements are rarely taken seriously. In tropical country like Malaysia which is characterized by high rainfall, the subsurface contamination problems are expected to occur. These areas are vulnerable to ground and surface water pollution. Seriousness of the pollution problem is unknown until specific detailed study is generally done.
The main environmental problem of waste dumping sites is the potential risk of groundwater pollution and subsequent influence on surface water quality. Waste disposal sites can affect local wells or tube wells used for domestic or industrial water supply.