A method for determining a sample filter clogging condition value of an immersion filter probe of a process water analyzer arrangement, the arrangement comprising the immersion filter probe arranged in a water basin and an analyzing unit comprising a water sample analyzer for analyzing a water sample filtered by the immersion filter probe, the arrangement comprising a bidirectional peristaltic hose sample pump for pumping a water sample from the immersion filter probe to the water sample analyzer, the sample pump comprising a peristaltic pump hose and a pump motor driving a peristaltic pump rotor, the pump motor being speed-controlled by a motor speed control, the immersion filter probe comprising a sample filter membrane being proximally mechanically supported by a support structure and having a membrane distal bulging volume, the arrangement comprising a bidirectional water flow sensor unit being arranged in-line with the sample pump and the water sample analyzer, and the arrangement comprising a filter clogging condition determination module for determining the sample filter clogging condition value of the sample filter membrane, with the method steps provided by the filter clogging condition determination module: driving the sample pump with a known rotational speed for pumping a defined filtration volume flowing in forward direction through the filter membrane and being detected by the water flow sensor unit, memorizing the filtration motor rotations value generated by the motor speed control for pumping the defined filtration volume, driving the sample pump for pumping a defined non-filtration volume detected by the water flow sensor unit, wherein the non-filtration volume is smaller than the membrane distal bulging volume, memorizing the motor rotations value generated by the motor speed control for pumping the defined non-filtration volume, and determining the sample filter clogging condition value based on the filtration motor rotations value and the non-filtration motor rotations value. the arrangement comprising the immersion filter probe arranged in a water basin and an analyzing unit comprising a water sample analyzer for analyzing a water sample filtered by the immersion filter probe, the arrangement comprising a bidirectional peristaltic hose sample pump for pumping a water sample from the immersion filter probe to the water sample analyzer, the sample pump comprising a peristaltic pump hose and a pump motor driving a peristaltic pump rotor, the pump motor being speed-controlled by a motor speed control, the immersion filter probe comprising a sample filter membrane being proximally mechanically supported by a support structure and having a membrane distal bulging volume, the arrangement comprising a bidirectional water flow sensor unit being arranged in-line with the sample pump and the water sample analyzer, and the arrangement comprising a filter clogging condition determination module for determining the sample filter clogging condition value of the sample filter membrane, with the method steps provided by the filter clogging condition determination module: driving the sample pump with a known rotational speed for pumping a defined filtration volume flowing in forward direction through the filter membrane and being detected by the water flow sensor unit, memorizing the filtration motor rotations value generated by the motor speed control for pumping the defined filtration volume, driving the sample pump for pumping a defined non-filtration volume detected by the water flow sensor unit, wherein the non-filtration volume is smaller than the membrane distal bulging volume, memorizing the motor rotations value generated by the motor speed control for pumping the defined non-filtration volume, and determining the sample filter clogging condition value based on the filtration motor rotations value and the non-filtration motor rotations value. driving the sample pump with a known rotational speed for pumping a defined filtration volume flowing in forward direction through the filter membrane and being detected by the water flow sensor unit, memorizing the filtration motor rotations value generated by the motor speed control for pumping the defined filtration volume, driving the sample pump for pumping a defined non-filtration volume detected by the water flow sensor unit, wherein the non-filtration volume is smaller than the membrane distal bulging volume, memorizing the motor rotations value generated by the motor speed control for pumping the defined non-filtration volume, and determining the sample filter clogging condition value based on the filtration motor rotations value and the non-filtration motor rotations value.