Reducing costs of controlling nonpoint source (NPS) pollution will be a high public priority in the next century. Compliance and transaction costs of reducing nitrogen runoff from dairies in the Lower Susquehanna Watershed by 40% are estimated for perfectly targeted and uniform performance standards. The perfectly targeted standard reduces compliance and transaction costs by almost 75% compared with the uniform standard. Future NPS control policies should use spatial information to target policy resources to priority concerns, areas, and farms. Further research is needed to lower the costs and increase the accuracy of spatial information.