Muslims do ablution several times daily and a considerable amount of water is consumed in this process. Rationalization of water consumption is a critical issue because of limited water resources in many countries and high cost of water purification or desalination. Various parameters affect the quantity of water consumed in ablution. Awareness about the importance of rationalization is needed as it is a key parameter in practice. Therefore, it can be claimed that the first step in modeling of water consumption rationalization in ablution is the identification of the most important of these parameters. In this research, the indicators of awareness level about effective rationalization of water consumption in ablution are determined and evaluated using the rough-set approach as a modern mathematical method. A 17-items closed questionnaire was designed and filled by different individual Muslims. This questionnaire addresses the awareness and actual behavior of these individuals regarding their practice in consumption of water. The primary purpose of this paper is to find the smallest sets of attributes having quality equal to the general quality of the defined characteristics in the information system. So, the number of parameters used in the modeling is reduced. To evaluate the results, the best algorithm of the defined attributes in the information system is identified by making use of the stepwise (stepwise linear regression) method and then, compare the results with each other. The results of the research indicate that the rough-set theory has a better and stronger operational capability in identifying the effective modeling indicators in measuring the awareness level about rationalization of water consumption in ablution. By taking advantage of these results, the amount of necessary data for measuring the awareness level about the rationalization of water consumption in ablution modeling is decreased and the speed and effectiveness of information processing are increased considerably