Costs and benefits of restoring wetlands for nonpoint source nitrogen pollution are calculated for two Swedish regions: the Stockholm archipelago and Gotland, an island in the Baltic Sea. Costs for reducing the load of nitrogen to the Stockholm archipelago by measures involving wetlands, agriculture, sewage treatment plants, and air emissions are calculated and compared. The results show that restoration of wetlands may be the least costly measure, SEK 20/kg nitrogen abatement as compared to the next cheapest measure, SEK 25/kg. The results from Gotland indicate that the benefits per unit of investment of restored wetlands may be three times as high as associated benefits of investment in sewage treatment plants. This difference in benefits is due to two factors: the joint production of several environmental services and the self-organizing feature.