Water pollution in swimming pools is extremely high. Infectious viruses, bacteria, fungi, dissolved and undissolved organic matter can be detected in every swimming pool. Chlorine is currently the most common disinfectant in swimming pools. Unfortunately, this disinfectant has many disadvantages: it promotes the formation of harmful compounds, has high water and energy consumption, an unpleasant irritating odour and creates toxic chlorinated compounds. These persistent chlorinated pollutants accumulate and have unforeseen long-term effects on human health. This leads to rapidly growing popularity of cleaner and more efficient technologies – water ozonation systems.