The U.S. Geological Survey's (USGS) National Water Information System (NWIS) is a comprehensive and distributed application that supports the acquisition, processing, and long-term storage of water data. USGS Water Data for the Nation Site serves as the publicly available portal to a geographically seamless set of much of the water data maintained within NWIS (additional background).

USGS Water Data for the Nation Site provides access to water data from over 1.5 million sites in all 50 States and additional border and territorial sites. The data are organized within the categories listed to the left.

The water data available via this site have been acquired as part of the USGS investigations of the occurrence, quantity, quality, distribution, and movement of the surface and underground waters that constitute the Nation's water resources. Additional information about the USGS and water resources of the Nation is available at water.usgs.gov.