Abstract. The devastating floods that swept through the Ahr Valley in July 2021 left indelible marks on the region's landscape and communities. Beyond the visible damage, experience from other events suggests an increase in mental health issues among those affected. However, there is a lack of data and understanding regarding the impact of flooding on mental health in Germany. Therefore, this study aims to determine how much the flooding in 2021 affected the population's mental well-being. For this purpose, a household-level survey (n = 516) was conducted in the district of Ahrweiler, Rhineland-Palatinate, Germany’s most affected region, one year after the flood event, i.e., in June/July 2022. The survey utilized a short epidemiological screening scale to determine the prevalence of people who show indications of suffering from post-traumatic stress disorder (PTSD). Using binary logistic regression analyses, we identify risk and protective factors that may have played a role in the development of PTSD to find intervention points for supporting those affected. Our findings reveal significant mental health issues one year after the flood event: 28.2 % of the respondents show indications of PTSD. Furthermore, this study has uncovered essential risk factors for developing indications of PTSD after flooding: female gender, getting seriously injured or sick during the event and feeling left alone to cope with flood impacts. The study emphasizes that severe flooding, such as the 2021 flood, results in new health-related needs that demand attention. As a result, care methods should be adapted to tackle the prevalence and risk factors connected with PTSD in the affected population.