Water-resources data for the 2003 water year for Texas consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 6 contains water levels for 880 ground-water observation wells and water-quality data for 158 monitoring wells. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas.