A method and a device for compensating leakage losses in a line system, in which at least one positive displacement pump and at least one shut-off member are provided, wherein the method and device can be used for the isobaric metering of liquid plastic components and wherein the actual liquid pressure in the system is determined by way of a pressure measuring device and, when the shut-off member is closed is regulated to a pressure target value by actuation of the positive displacement pump, wherein the conveying loss rate of the positive displacement pump, which ensues to maintain the pressure target value when the shut-off member is closed is added to a target delivery rate in order to compensate for the leakage loss occurring at the corresponding pressure target value.