The objectives of this research were to assess the effects of hybrid hydrodynamic cavitation on advanced oxidation processes based on ozone (O3), hydrogen peroxide (H2O2) and UV light for drinking and swimming-pool water treatment. Attention was paid to the changes in the removal efficiency of the target pollutants and specific energy consumption to achieve the same order of target pollutant removal. Changes of the characteristic operational parameters were more closely followed. The reaction times up to 20 minutes were considered preferential. Ozonation alone and the combinations of H2O2/O3, H2O2/UV and O3/UV advanced oxidation processes were applied in the experiments. As a mechanism of the process optimization, hybrid hydrodinamic cavitation was added to the process. The experimental setup was designed as a semi-batch scale-up system and utilized the reaction volumes of 50%83 L. Based on the obtained results we could confirm that the application of the hybrid hydrodynamic cavitation, under the applied experimental conditions, was able to improve the efficiency of treatment by ozone, H2O2/O3 and H2O2/UV advanced oxidation processes. Further, conditions of low number of passes through the system (3%12) were sufficient to exploit the beneficial effects of hybrid hydrodynamic cavitation and the reaction times up to 20 minutes were proven to be sufficient. Under herein described experimental conditions, the application of hybrid hydrodynamic cavitation could in some cases be at least as energy efficient as the O3, H2O2 and UV based advanced oxidation processes alone. These results were most evident when the ratios between the dosages of the applied oxidants or UV light and concentrations of the target pollutants in the samples were relatively low. Special attention needs to be paid to the formation of the by-products of the advanced oxidation processes. This is of yet greater importance when previously treated drinking or swimming-pool water is subjected to subsequent oxidation or disinfection by chlorine and especially if hybrid hydrodynamic cavitation is applied together with the advanced oxidation processes.