ABSTRACT: The U.S. Geological Survey (USGS) began an extensive ground- and surface-water quality study in July 1989 to define the baseline water quality within a southeastern Florida drainage district and to develop a data base for future water-resource planning and management. Results were published in a USGS report (Lietz, 1996), comparing ground- and surface-water quality data (1989-94) to the Florida Department of Environmental Regulation Class I drinking-water standards. This Fact Sheet presents an additional 4 years of water-quality data and summarizes water-quality trends over the entire 10-year sampling period (1989-98) for selected sites and constituents.