The Sixth Edition has been thoroughly updated to include several new federal and state cases, legislation, and administrative regulations. The authors have included material and case studies on many other recent developments that are not yet fully reflected in cases and statutes. Some of those case studies, including the management of the Great Lakes, the multi-million dollar aquatic ecosystem restoration program in the Bay-Delta, efforts to protect endangered species, and the aftermath of the 2002 water cut off for farmers in the Klamath River Basin have been expanded and updated. Each chapter contains significant new material. Although the organizational approach for these initial chapters is new, the majority of the cases in them will remain familiar to users of earlier editions. However, the first part of Chapter 8, which deals with local water distribution organizations, has been compressed by eliminating the principal cases. New material on adequate water supply laws has been added.