Building on theories of environmental federalism, policy implementation, and professionalism, this study analyzes the effects of executives’ professions on American water utilities’ compliance with the US Safe Drinking Water Act (SDWA). Using original data from a unique survey of American water utility chief executives, the EPA’s Safe Drinking Water Information System, and a variety of other sources, I find that utilities that are led by professional engineers violate the SDWA significantly less frequently than do utilities led by non-engineers. These results highlight the importance of local administration in effective environmental policy within a federal framework. At a theoretical level, results indicate that executive professions are significant and heretofore unexamined factors in the local implementation of federal regulations.