Local policy networks can aid federal agencies, but they can also coopt federal resources for unintended purposes. Our empirical study finds that effective local networks increase both enforcement and compliance rates for the Clean Water Act. We discuss the circumstances under which effective networks can transform political culture, enhancing enforcement and compliance even in conservative areas generally opposed to regulation. The modified detection-controlled estimation procedure enables us to utilize official enforcement records from 1994 to 2000 to study both enforcement and compliance.