Water-resources data for the 1972 water year for California include records of data for the chemical and physical characteristics of surface and ground water. The distribution, type, and number of stations in each river or drainage basin are shown in figure 1. A few pertinent stations in bordering States are also included. The records were compiled by the Water Resources Division of the U.S. Geological Survey under the direction of R. Stanley Lord and Lee R. Peterson, successive district chiefs. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in California.