Wastes generated due to human activities pose a threat to the environment, and their safe and economical disposal is warranted. Landfilling of these wastes is still the most widely practised and viable alternative for their disposal. This is usually accomplished by using engineered waste containment systems in which compacted liners of predominantly clay soils are employed between waste and natural ground to act as barrier to chemical leaching. It follows that the design hydraulic conductivity of the clay is a governing parameter and many environmental regulations require this parameter to be less than 1x10"' m/s. Therefore, the precise assessment of hydraulic conductivity and the compatibility of the liner material with the permeant or leachate encountered, is paramount to ensure the effective performance of the clay liner. This thesis reports the test results of the compatibility and hydraulic conductivity of some Victorian soils used for liner construction.