The purpose of this paper is to consider an environmental policy from a perspective of the residents on the shore of Lake Kasumigaura. So far, various policies were attempted against the considerably polluted water of Kasumigaura, the second largest lake in Japan. Some of these policies, for example, were to enlighten people’s environmental consciousness or to control the water pollution. However, most of these attempts were not remarkably effective. Therefore, this paper tries to understand the residents’ image of Kasumigaura by referring to the religious symbol of the shore, Suijin, a sort of guardian deity of water.
　　　By looking at the functions and the distribution of Suijin throughout Kasumigaura, the paper clarified how the residents maintain the relationship with Suijin. Firstly, people by the shore communicate with Suijin through community. Secondly, their relationship was intentionally maintained durable through the lasting character of community. Furthermore, through the Suijin’s mediation, the residents on the shore pursue the relationship with the lake Kasumigaura at the aspect of Buji, a status of safe and calm social relationship.
　　　From the above investigations, the paper argues that the environmental policy has to secure the social relationship in the local communities, which enable the residents to communicate with the lake.