In accordance with guidelines set forth by the Office of Water Quality in the Water Resources Discipline of the U.S. Geological Survey, a quality-assurance plan has been created for use by the U.S. Geological Survey (USGS) in Miami to conduct water-quality activities. This quality-assurance plan documents the standards, policies, and procedures used by the Miami USGS for activities related to the collection, processing, storage, analysis, and publication of water-quality data. The policies and procedures that are documented in this quality-assurance plan for water-quality activities are meant to complement the Miami USGS quality-assurance plans for surface-water and ground-water activities.