The qualitative effects of stormwater infiltration on soil and seepage water are investigated with long term numerical modelling. The retention behaviour of different soils and materials used in infiltration devices is determined with batch and column tests. Results of the laboratory tests are adsorption isotherms which represent input data for numerical transport modelling. The long term simulations are performed with combinations of different solutions (types of roof runoff) and infiltration devices (swale and trench) under different hydrogeological conditions. The presented results contain the infiltration of low polluted roof runoff, runoff from a roof with zinc sheets and from a roof with copper sheets concerning the heavy metals zinc, copper and lead. The increase of concentrations in the infiltration body is high. For the infiltrated water, the results show a migration to groundwater only for the low adsorbing soil.