The paper presents the equipment of an installation for restoring the productivity of water intake wells through longitudinal circulation-reagent treatment of the filter and the filter-adjacent zone. The equipment includes a reagent tank, a diaphragm pump placed above the water level in the well, a pipeline system, and a resistance element placed with an annular gap inside the filter being cleaned, ensuring uniform filter declogging along its entire length. The treatment technological process is described, which involves the continuous circulation of the reagent by the pump in the annular channel formed by the inner impermeable walls of the corrugated element and the outer permeable walls of the filter. Through the filter's openings, the reagent penetrates into the filter-surrounding zone and ensures uniform decolmatation of the gravel pack. The key advantages of the proposed solution are substantiated: increased efficiency of filter and filter-surrounding zone decolmatation, reduced energy consumption, and the ability to use a wide range of reagents, including sodium dithionite. Furthermore, the proposed solution reduces the labor intensity of technological operations performed by personnel when treating wells with decreased flow rates. Calculated flow schemes for two operational modes of the equipment are provided: 1) continuous reagent circulation in the system “diaphragm pump – injection pipeline – well filter – suction pipeline – diaphragm pump”; 2) pumping of the waste solution from the well into the tank. For these modes, equations of motion for the reagent and reaction products were compiled and solved using a graphoanalytical method. The presented hydraulic calculation methodology allows to obtain values of circulation flow rate and flushing velocity depending on the static water level in the well, the geometric dimensions of the filter and pipelines, and to select the necessary technological equipment. An example of calculation is given.