The invention is directed to a method for determining a sample filter clogging condition value (C) of an immersion filter probe (20) of a process water analyzer arrangement (10), with the method steps provided by a filter clogging condition determination module (60):
driving the sample pump (40) for pumping a defined filtration volume (FV) flowing through the filter membrane (24) and detected by the water flow sensor unit (50),
memorizing the filtration motor rotations value (FR) generated by the motor speed control (61) for pumping the defined filtration volume (FV),
driving the sample pump (40) for pumping a defined non-filtration volume (NV) detected by the water flow sensor unit (50), wherein the non-filtration volume (NV) is smaller than the membrane distal bulging volume (MV),
memorizing the motor rotations value (NR) generated by the motor speed control (61) for pumping the defined non-filtration volume (DV), and
determining the sample filter clogging condition value (C) with the filtration motor rotations value (FR) and the non-filtration motor rotations value (NR).