Abstract: A method is provided to characterize the nature of a washing fluid by measuring the turbidity and conductivity changes during preselected periods, such as rinse sequences. More specifically, the plateau magnitudes, and variability magnitudes, are measured during each of the rinse sequences of a washing procedure and used as input parameters to a fuzzy logic engine. Calculations are performed in order to characterize the fluid as a function of the input parameters. The characterization of the washing fluid is done in terms of the solubles and suspendeds in the fluid and the cycle state of the fluid. The solubles represent chemical elements in solution within the washing fluid and the suspendeds are particulate matters suspended in the fluid. The cycle state represents the aggregation of the solubles and suspendeds in the fluid.