Nutrient leakage into streams and rivers can lead to eutrophication, which negatively impact aquatic ecosystems. A commonly used tool to mitigate nutrient leakage is the implementation of wetlands into the polluted system. This study focuses on the levels of N and P in the river Fyris.n in Uppsala, Sweden, and the possible effects from restoration of a wetland near the river’s outlet. The results show a potential reduction of 41% and 45% for N and P respectively. The results point to a need for more wetlands further up in the catchment system to mitigate the nutrient load in the subcatchments, as the high nutrient levels there would not be affected by the proposed wetland. There are also several uncertainties due to the lack of reference material, and the results proves the need for further studies on this subject.