It is a well-known fact that pollution in the lakes and marshes (e. g. Lake Kasumigaura etc.) and their catchment areas has increased since the 1960's. It has been caused by the increase in socio-economic activities, such as advancement of industry and consumption increase in household economy. To solve such a problem, many studies in various fields (e. g. chemistry, bionomics, ecology etc.) are being carried out for investigating the process of deterioration of the water quality and improvement of technologies. From the viewpoint of social science, we also have numerous studies, analyzing political aspects of the environmental problems and socio-economic activities. However, it is necessary to take into account the views and opinions of the residents living around the lake on the issue of deteriorating the water quality and ways of improving the water quality. In this study, we try to estimate the residents' evaluation of the water quality of Lake Kasumigaura and relate their experience based opinions to the pollutants represented in the chemical symbols of elements to build a residents' model in order to analyze within the social environment model.