Lake Houston serves as the source of drinking water for approximately 4% of the population of the City of Houston, and it also serves as a major recreational resource. Rapid development of the western portion of the lake's watershed has led to deterioration of lake water quality, raising concerns over continued present and future use. In response to concern over observed sporadically high levels of fecal coliform bacteria, research was undertaken to investigate bacteriologic water quality. The objective of this research was to evaluate yearly, seasonal and spatial water quality trends and correlations of bacterial densities to physical and chemical water quality parameters. Information gained during these studies may be used in further evaluation and control of sources of bacterial pollution and to delineate periods when bacteriologic water quality may be unsuitable for such uses as contact recreation.