Until recently, when calculating water intakes laid in the weathering zone, the filtration homogeneity of fractured rock massifs was assumed; the decrease of their water permeability with depth was not taken into account, which led to inevitable errors. L.V. Borevsky proposed a method of calculating the water inflow to the well, based on the condition that the rock filtration coefficient in the weathering zone decreases with depth according to a linear law. It has allowed to specify considerably calculations of water intakes.