Throughout this book we have provided the reader with a description of how the EPA and state NPDES personnel enforce the law, as well as an explanation for why they have adopted these enforcement strategies. In short, our theory is that the diverse nature of the regulatory environment under which surface-water pollution control enforcement occurs has promoted a pragmatic approach to enforcement problems and the employment of broad bureaucratic discretion by agency personnel. In Chapter 3 we described how this pragmatic enforcement operates in actual practice. We also argued that one by-product of the pragmatic enforcement style is the employment by EPA personnel of considerable bureaucratic discretion. In Chapter 4, Rouse and Wright used survey data to demonstrate that EPA NPDES personnel perceive themselves as exhibiting considerable discretion in their implementation of the Clean Water Act. In Chapter 5, Hunter, Waterman, and Wright then demonstrated that discretion results in considerable variation in enforcement across the EPA's ten regional offices. In Chapter 6 we then showed how similar variations in enforcement can be identified across the fifty states and began the process of explaining these variations by examining several factors related to organizational structure. Then in Chapter 7 we provided an empirical analysis that demonstrated that these variations can largely be explained with reference to the diversity of the regulatory environment itself. Finally, in Chapter 8 we showed that the diversity of the regulatory environment is related to policy outcomes as well, but not in the hypothesized direction. Our analysis of policy outcomes raised concerns about environmental justice and the adequacy of important organizational structures, as well as the need to derive better measures of water quality.