We use hedonic techniques to show that water quality has a significant effect on property values along the Chesapeake Bay. Mindful of the limitations of using hedonic methods for welfare analysis, we calculate the potential benefits from an illustrative (but limited) water quality improvement. Past hedonic studies have almost entirely ignored the potential for omitted variables bias -- the possibility that pollution sources, in addition to emitting undesirable substances, are likely to be unpleasant neighbors. We discuss the implications of this oversight, and we provide an application that addresses the problem head-on.