Membrane filtration organic compounds from naturally coloured water for drinking water and industrial water supply is becoming increasingly widespread. The distinction between membrane rejection and plant treatment efficiency is often overlooked. It has been shown that if more than 60% recovery of the feed water is desired, the plant efficiency will be significantly lower than rejection. Recirculation of concentrate will increase the concentration of organics in the membrane modules, but the reduction of concentration polarization from the increased crossflow will typically compensate this and little loss in treatment efficiency is experienced. Flux has low influence on treatment efficiency, but water characteristics has. Therefore recovery rate and water characteristic are the most important variables for plant treatment efficiency and should be included in plant design and dimensioning.