Nitrate excess in rivers is caused by anthropogenic nitrogen sources, such as agriculture and wastewater. Diffuse sources stemming from agricultural fertilization can remain in the soil for long periods of time as a legacy and are mobilized through hydrological pathways that connect sources with rivers. Previous studies show that drought periods can increase nitrogen stored in the soil due to lower nitrate transport to streams and less nitrate uptake by plants due to dry conditions. This accumulation of nitrogen during drought and its subsequent transport under wet conditions during the post-drought period can result in high nitrate concentrations in rivers.In our study, we analyze the nitrate response of 190 German rivers during hydrological post-drought conditions from 1978 to 2019. We define droughts as periods with more than 30 consecutive days of discharge deficit using a variable threshold method and post-droughts as 100-day periods following the termination of a drought. We particularly focus on post-drought periods in the winter season that display the most pronounced concentration anomalies. Our results show that during the winter post-drought period, 66% of the catchments export higher nitrate concentrations compared to non-drought conditions, with 19% of the catchments exporting significantly higher nitrate concentrations (Kruskal-Wallis test, p-value