In-line filter for diesel and petrol with 30 microns – cartridge for the absorption of water that is eventually present in the storage tank. The water could particularly become dangerous for the diesel motors of the latest generation. The filter continuously absorbs the water which after some time will cause a reduction of the delivery and also a loss of head of the diesel supply unit. Therefore the waterlogged cartridge must be replaced then. The filter can be installed on the suction side as well as on the delivery side of the diesel supply unit.