Growth of an external filter cake with its final stabilization has been widely reported for waterflooding in oilfields, well drilling, fresh water storage, and industrial waste disposal in aquifers. We derive the mechanical equilibrium equation for stabilized cake accounting for electrostatic force and for varying permeate force factor. The main empirical parameter of the model, highly affecting the stabilized cake prediction, is the lever arm ratio for the particle on the cake surface. The lever arm ratio was calculated from laboratory cross-flow filtration experiments and from well injectivity data. It was also determined from Hertz's theory for the elastic particle deformation on the solid cake surface. Good agreement between the results validates the developed mechanical equilibrium model with the lever arm ratio determined from the elastic particle deformation theory.