Water that floods the mining complexes is drained on a constant basis when a mine is still active, but the situation changes the moment the mine is closed. This article presents the influence that flooding of mine workings has on a surface of a mining area using computer simulation. The evaluation of potential changes to the surface and scale of this phenomenon has been done using as examples the exploitation of mine deposit layers 702, 705, and 718 of the old Gliwice and Pstrowski mines. The performed numerical simulation showed that using numerical modeling of rock mass demonstrates the possibility of predicting uplifting of the surface caused by flooding of underground workings. Maximum designated value of surface uplifting amounts to around 34 mm/m. This value is relatively small and does not exceed 2% of subsidence caused by previous mining activity.