Electronic journal "Trudy MAI" . Issue No71 — 23 s. The article suggests ways to calculate the cavitation stock corresponding to the beginning of cavitation and failure. On the basis of experimental data published in the literature, empirical formulas for the initial cavitation coefficient. are obtained. In addition, a simulation of a three-dimensional non-stationary turbulent flow in the impeller . was performed. In the case of a straight lattice of plates of final thickness from the equations of flow, energy and amount of motion, a breakdown cavitation reserve shall be calculated. The obtained data are summarized in the case of a circular lattice of a centrifugal impeller. All this makes it possible to reasonably select the allowable cavitation reserve of the centrifugal pump .