This report presents the assessment of the planned water reuse scheme at Le Jaunay reservoir (Vendée) in its potential risks for human health and ecosystems, and also in its overall environmental impacts. Methods of risk assessment (quantitative microbial and chemical risk assessment) and Life Cycle Assessment are used to characterize the potential hazards associated with the use of reclaimed water, but also the environmental benefits compared to other options for additional drinking water supply. The assessments show that water reuse can be operated without unacceptable risks for humans and the environment, and that it is competitive to other options of water supply in its energy demand and greenhouse gas emissions. Data quality should be improved in a demonstrator phase to validate the outcomes of this first assessment.