In the United States, the federal government is increasingly relying on local governments to implement policies that address the nation's lingering environmental problems. Yet, little is known about the factors that influence local level implementation of a federal mandate. This paper explores local government response to the NPDES Phase II Stormwater Program in California and Kansas by investigating local conditions, perceptions of the federal program, and implementer characteristics. The study found that fiscal resources, a well-educated public, positive perceptions of' the federal policy, and co-operative planning efforts lead to better compliance with the mandate and a higher quality response.