In this research the scientific dynamic process is studied concering
water filtering in Mosul city through employing the input and output variables represented by some tests which were performed on raw water
before the filtering process, to be treated later through the numerous filtering stages.
The tests involved: the electrical conduction, turbidity, water PH, and water temperature The same tests were conducted after the filtering process to guarantee that water is good for human consumption and to guarantee the validity of these tests as well and also to ensure that these tests meet the Iraqi Standard specifications before adding the chlorine. Four models were constructed through this study concerning the dynamic filtering process of the transfer functions with a single input for the four tests. And then models were built for the four transfer functions as input multiple series before filtering. Each of the four tests represented the output series by itself and consequently four models of transfer functions were obtained with multiple inputs and a single output variable in order to observe the range of impact for the output variable with the multiple input variables and using these models in Forecasting and then comparing the single input models and the multiple input models by means of using the standards of Forecasting control accuracy. The results showed that the electrical conduction model and the multiple input PH value were better than the results of the single input and the turbidity model of single input was better in comparison with the results of the multiple input. In addition to that, results showed that the temperature model for the single and the multiple input are similar.