Farm sustainability is becoming an increasingly important issue to European agriculture. However, fertilizer leaching to groundwater is still a major concern for Greek agriculture. The impact on the maximum potential short-run profit and yield, when fertiliser application dose is limited to certain point, was examined, using Data Envelopment Analysis (DEA). Spring potato farmers were found to apply rather high doses of chemical fertiliser, which poses high potential risk for nitrate and phosphorus leaching to groundwater. However, restricting nitrogen application to the doses recommended by agronomists would imply only little economic and yield sacrifices on potato farms,but resulting to significant reduction to potential environmental risk.