The paper lists the existing technological schemes for the purification of flushing water of water treatment facilities; shows the results of a multifactorial central composite planning experiment with the obtained second-order correlation and regression analysis equations describing the dependence of the residual content of suspended solids on the initial content, sedimentation duration, coagulant dose when using various reagents; the recommended technological scheme for the purification of flushing water with technological calculation of the main structure.