The paper contains comparison of basic physico-chemical and water properties of reclaimed and not reclaimed soda waste reservoirs of the former Cracow Soda Plant “Solvay”. Technical reclamation of the post soda waste reservoirs based on covering them by 30 cm thick layer of mineral ground. On the base of laboratory work it was ascertained, that layer of ground used for technical reclamation did not improve water properties for plant in general. The layer used for reclamation was characterized by lower storage of water available for plant than adequate layer for not reclaimed waste reservoir. By comparison of pH values it was stated, that on the reclaimed reservoir reaction in upper layers was lower (about half of the pH unit) than in the adequate layers in not reclaimed reservoir. Upper layers of not reclaimed reservoir had a tendency to higher vales of electric conductivity than adequate overlayer of reclaimed one. In a case of overlayer electrical conductivity does not exceed permissible limit which is usually accepted for plant at the level 1.0 dS·m–1.