Objective. To evaluate the effectiveness of photocatalytic methods of oxidation of organic substances for the preparation of drinking water. To show the expediency of the use of the described method for the design of wastewater treatment facilities.Materials and methods. The oxidation degrees of 58 organic substances of various hazard classes were studied. The sampling frame was based on two characteristics: origin (biological and artificial) and the oxidation state stated in different sources.Results. A high efficiency of photocatalysis for the destruction of organic substances in wastewater from various industries has been shown: the degrees of oxidation range from 70 to 100 %.Conclusion. Photocatalysis can be used to design wastewater treatment facilities with a view to reducing the probability of biological pollution of natural waters intended for drinking water production.