USGS Water Data and Information

U.S. Geological Survey (USGS) water data and information is valuable to the public, researchers, water managers, planners, and agricultural users, especially during floods and droughts. Scientists at the USGS have measured streamflow and groundwater levels to assess water resources since 1879.

The USGS provides the most extensive set of historical streamflow and groundwater data available to the public. Water data is quality assured by employing standardized techniques used across the country. The uniformity of the dataset allows for multi-state comparisons and other comparative statistical analyses that inform policy makers of water resource availability and quality.

	Surface Water (Streams, Lakes, and Reservoirs) Access surface-water resource data and information in Maryland, Delaware, and the District of Columbia, including freshwater flow to the Chesapeake Bay and coastal storm surge and tide gage monitoring.
	Groundwater (Groundwater Aquifers and Wells) Find out more about groundwater resources and information in Maryland, Delaware, and the District of Columbia.
	Monthly Groundwater and Streamflow Response to Weather Select climate indicator wells and streamflow sites, plus precipitation and reservoir data, are used to summarize water resources in the Maryland, Delaware, and District of Columbia's region.
	Water Quality Learn about water quality, such as chemical and biological contaminants, and the physical conditions of streams in Maryland, Delaware, and the District of Columbia.
	Water Use Find out more about water use and withdrawals in Maryland. Withdrawal data is identified by water type: groundwater and surface water (fresh and saline), and by water use category.