Floods lead to adverse impacts not only in financial terms but also on the health of the exposed population. We report the health-related Quality of Life (QoL) and functioning in the population affected by the 2021 flooding in Germany using an empirical survey dataset collected in November and December 2022. Health-related QoL and functioning of flood-affected population is represented by two scores - 1. The EuroQoL 5D Visual Analog Scale (EQ-5D VAS) and 2. the score of the 12-Item WHO Disability Assessment Schedule (WHODAS) 2.0, respectively. By applying an incremental linear regression model and an ensemble of Machine Learning (ML) models, we infer that health-related QoL and functioning are strongly negatively related to the psychological burden from those being affected by the flood event. This includes how often they think about the traumatic event. Home owners were found to have worse QoL and functioning than tenants. Household income and ability to repair/reconstruct flood damages – in specific, insurance benefits, private donation and satisfactory claims compensation are associated with high QoL and functioning in flood-affected populations. These findings highlight the importance of strengthening the mental health of flood affected populations in order to help reduce the psychological burden of the flood event. Additionally, the study emphasizes the strong positive association between physical/financial recovery and QoL and functioning of flood-affected populations.