Water resources are an important guarantee for human life, and the health of the water environment directly affects socioeconomic development. With the rapid development of urbanization and industrialization, wastewater has a huge impact on the water environment. The assessment of water environmental risk has become an important measure for long-term sustainable development. In this study, we proposed a framework based on the pressure-state-response (PSR) model to assess and analyze the changing tendencies of the water environment carrying capacity (WECC). The results showed that WECC increased from 2011 to 2017 and the evaluation status changed from very unhealthy (V) to basically healthy (II). Compared with the carrying capacity of each indicator, the most influential factors were the amount of chemical oxygen demand (COD) discharged, water consumption per capita, industrial water consumption increment per 104-yuan, greenbelt area per capita, the wastewater processing capacity of industrial facilities, and the amount of industrial wastewater. This study concisely shows the status of the water environment in Ningbo and accurately identifies the key problems of water quality. The assessment and analysis of water environmental risk can be a scientific and effective reference for social development planning. By decreasing the amount of wastewater and improving the water quality, WECC can be kept under control for a long time.