In recent years, there has been an increasing shortage of fresh water suitable for irrigation, which does not subsequently cause soil salinization. To solve the above problem, it is necessary to reconstruct the collector-drainage system into a circulation system. Using the example of open collectors, the dynamics of the chemical composition during the growing season was studied, which showed its dependence on the intensity of irrigation, the salinity of irrigation water, and the seasonal amount of precipitation. A comprehensive assessment of the suitability of water from open collectors for irrigation in terms of salinity, chloride salinity, sodium and magnesium alkalinization and soda formation has been carried out. The necessity of additional treatment of drainage and waste waters to exclude soil salinization has been established. Technical solutions for the purification of the drainage runoff in the stream and with the help of a mobile treatment plant are proposed. A diagram of a removable filter cassette operating in a honeycomb type for water purification in a stream is presented.