The pressure flow of slurries may exhibit peculiar pseudo-homogenous conditions when finer particles form a homogenous mixture, resulting in the alteration of the rheological properties of the conveying fluid, while coarser particles move partially separated. With reference to such conditions, the aim of this paper is to define a new design criteria for pipeline systems used for the prevention of reservoirs’ silting up, and also for rehabilitation. Only empirical resistance formula are currently available, but they are not specified for pseudo-homogenous conditions. An approach based on the rheology of sediment mixtures is therefore proposed within this paper.