A brief review of existing methods of calculating the coefficient of filtration (k). Of the existing and currently recognized methods of determining k by infiltration from pits, the method of A. K. Boldyrev is the most widely used, but obviously inaccurate, and only the methods of N. S. Nesterov and N. Y. Denisov combine the simplicity of calculation and sufficient accuracy. Their methods, in fact, only take into account, but do not take into account the complexity of the infiltration process. The whole process is as if excluded from the experience by the very construction of the method. In other words, the experience is made in a form that allows the calculations to consider only a part of the “water body” with the simplest water movement (N. S. Nesterov) or to solve a system of equations, in each of which the complexity of the movement is fixed by a simple coefficient (N. Y. Denisov). But these methods require either special equipment (N. S. Nesterov) or are too cumbersome to perform (by N. Y. Denisov). However, even N. S. Nesterov's method is not accurate enough, because in the central part of the “water body” he singled out, water particles move not only vertically, but also sideways.