Damage of the waterproofing system in a waste material depository or sewage sludge composting plant and the penetration of pollutants into the soil and groundwater may cause an environmental mishap. Although the standard waterproofing technologies are extremely safe, one cannot disregard possible malfunctions. For a well-established plan of managing unexpected events, the impact of such damage must be forecast. With the help of models described in the relevant literature, we propose the basic ideas used in simulations for two planned regional waste material depositories, a planned sewage sludge composting plant and an active aluminium dross depository of a foundry.