Whilst life cycle assessment (LCA) boundaries are expanded to account for negative indirect consequences of bioenergy such as indirect land use change (ILUC), ecosystem services such as water purification sometimes delivered by perennial bioenergy crops are typically neglected in LCA studies. Consequential LCA was applied to evaluate the significance of nutrient interception and retention on the environmental balance of unfertilised energy willow planted on 50-m riparian buffer strips and drainage filtration zones in the Skåne region of Sweden. Excluding possible ILUC effects and considering oil heat substitution, strategically planted filter willow can achieve net global warming potential (GWP) and eutrophication potential (EP) savings of up to 11.9 Mg CO2e and 47 kg PO4e ha−1 year−1, respectively, compared with a GWP saving of 14.8 Mg CO2e ha−1 year−1 and an EP increase of 7 kg PO4e ha−1 year−1 for fertilised willow. Planting willow on appropriate buffer and filter zones throughout Skåne could avoid 626 Mg year−1 PO4e nutrient loading to waters