The term basement has different meanings depending upon the discipline it is used in and the purpose of using the term whether it is purely descriptive or used in analytical and numerical models. In geology the term basement often refers to the first encounter of igneous, metamorphic or plutonic rock that could occur at the surface or at great depth. Strictly speaking in hydrogeological terms a basement could be an aquifuge, which contains zero porosity and no water as well as zero permeability or an aquitard that contains storage but effectively zero permeability. As groundwater scientists we understand that these conditions are rarely if ever meet. Notwithstanding this, we in the hydrogeological community often make a decision on the so-called hydraulic basement knowing that it most likely is not strictly correct. Our chosen basement occurs at the bottom of the zone that we are interested in modelling and we assign the boundary condition as a zero flux or no flow boundary. For example this basement could be an aquitrad at the bottom of an unconfined aquifer or a crystalline rocks at the bottom of a stacked sequence of aquifers. However, as discussed by Tóth (Tóth 2009, 2016) the emerging new view of hydrogeological science is that no geological material is impervious and leakage between different units is of paramount importance in the development of conceptual and numerical models. In this presentation we compare the classical benchmark simulations of 2D flow by József Tóth (Tóth 1962, 1963) by adding basement head or flux conditions to induce downward flow in under-pressurised conditions and conversely upward flow in over–pressurised conditions. Single and multi-hydraulic conductivity layers as well groundwater ages are examined.