This white paper, Distributed Sensing Systems for Water Quality Assessment and Management, describes the technological state of the art and examines the potential for using distributed sensing systems to improve the management of critical water resources. The paper also outlines recommendations for further research to advance the development and use of these systems by environmental resource managers. The white paper, released at an event at the Wilson Center on February 23, 2007, was prepared by scientists and engineers at the Center for Embedded Networked Sensing for the Wilson Center's Foresight and Governance Project with support from the Environmental Protection Agency's Offices of Water and Research & Development, with assistance from the Office of Air & Radiation.