A pour flush toilet has a water seal. The problems associated with odor and insects are avoided by having the water seal. Excreta deposited in the latrine pan is flushed by pouring 2 to 3 liters of water into it. The mixture is directed into a pit in the same way as for a pit latrine. The processes of biodegradation of organic wastes in the pit are exactly the same. More water percolates through the soil surrounding the pit and the potential for groundwater pollution is higher. Hence, a pour flush toilet with a pit is not suitable when groundwater table is close to the surface. (UNEP 2000)