The results of the 1963-1967 Water Quality Survey of the Galveston Bay Complex indicate water qualities at specific locations varying from very poor to excellent. In order to arrive at conclusions as to the four questions outlined in the Objectives (1. Are the Galveston Bays polluted, and if so to what extent?, 2. Is the Houston Ship Channel polluted, and if so to what extent? 3. Is Clear Lake polluted, and if so, to what extent? 4. What are the long-term trends of water quality of the various portions of the Galveston Bay complex, bacteriologically and chemically? Are we losing or gaining in water quality?) it must be realized that water satisfactory or unpolluted for one beneficial use may be unsatisfactory or polluted for another beneficial use. For the purposed of relative evaluation for recreational uses, however, it is stipulated that the two parameters, the numerical average of all the biochemical oxygen demands results (B.O.D.) and the logarithmic average of all the most probable number of total coliform bacteria per 100 ml have been applied.