U.S. Geological Survey National Water Information System

The National Water Information System (NWIS) is the Nation’s principal repository of water resources data, offering current and historical streamflow, groundwater level, and water quality information.  Additional tools are provided here to help find data in NWIS, in other USGS products and services, and from other federal partners and national organizations.  If you do not find what you need contact a local USGS Water Science Center.