The data obtained from underwater inspections have shown that the structures of the Kaunas hydroelectric station are operating reliably and there have been no deformations threatening stability during the eight years the hydroelectric station has been in service. Underwater inspections carried out by hydraulic engineering experts using lightweight diving equipment have big advantages over inspections carried out by professional divers, from the standpoint of the quality of the inspection, overall operation, and small expenditure in time and equipment.