This report provides a regional assessment of water quality for the San Jacinto-Brazos coastal basin. The objectives of this basin assessment are: (1) provide the Water Commission, river authorities, and local governments with information to take appropriate corrective action to meet water quality goals; (2) identify problem areas in order to focus resources and future studies on these areas; (3) insure that the assessment is comprehensive; (4) develop a cooperative partnership between river authorities, designated local governments, other political subdivisions, other state agencies and the Texas Water Commission in identifying and addressing water quality problems within basins; (5) avoid duplication of water quality protection efforts; (6) accomplish the assessment in 2 phases, one to gather the information and one to analyze and evaluate the collected information; (7) involve citizens and private organizations in efforts to protect water resources; and (8) make better use of existing information by converting it into more accessible formats and allowing use by others besides Texas Water Commission staff.