The USGS National Water Information System (NWIS) contains extensive
water data for the Nation. Public access to many of these data is
provided via NWISWeb
(additional background).
The Ground-Water database consists of
more than 850,000 records of wells, springs, test holes, tunnels,drains, and
excavations in the United States. Available site descriptive information
includes well location information such as latitude and longitude,
well depth, and aquifer.
The USGS annually monitors ground-water levels in thousands of
wells in the United States. Ground-water level data are
collected and stored as either discrete
field-water-level measurements or as
continuous time-series data from automated recorders. Data from
some of the continuous record stations are relayed to USGS
offices nationwide through telephone lines or by satellite
transmissions providing access to
realtime ground-water
data. Once a complete day of readings are received from a
site,
daily summary data are generated
and made available online. Annually, the USGS finalizes and
publishes the daily data in a series of water-data reports.