A new method of yield evaluation for pressure-driven membrane processes is presented in this paper. The method enables the flux to be estimated based on a simple experimental procedure. The permeate flux is determined by means of a modified surface renewal concept, instead of the commonly used film model. The main advantage of this approach is the possibility of describing the limiting flux and flux decline phenomena, which are important in designing and controlling membrane processes. The experimental results on microfiltration and ultrafiltration in various module types support the feasibility of the proposed approach.