In the article there were presented the changes of water hazard state in coal mines during last several years. On the basis of recognition of conditions of conducted and planned mining exploitation there was presented the example of water hazard assessment for mining exploitation planned near abandoned flooded mines. On the example of planned mining exploitation in the conditions existing in the Upper Silesian Coal Basin there was also presented the methodology of safety zones determining in active mines separating them from water reservoirs with their capacities up to millions of cubic meters of water.