The study presents an analysis of the methods of purification of natural and waste waters used in various branches of industry, agriculture and public utilities, as well as in the processes of water treatment and purification of natural and waste waters of individual industries, enterprises and organizations. Based on the results of the analysis, a device is proposed for the implementation of a complex method of reagent-free purification of natural and waste waters, which is two functional units of preliminary purification and settling, ensuring an increase in the efficiency of water treatment due to the rational organization of purified flows, simplification of the design due to the exclusion of moving parts and units, and an increase in the reliability of the system for cleaning natural and waste waters.