Water Resources of the United States

A-Z Index of hydrologic terms


National Water Information System

View current and historical streamflow, ground-water level, and water-quality data

Today's Water Conditions

View comparisons of current and historical conditions using maps
Click map to go to current water resources conditions in the U.S.



USGS Water Science Centers are located in each state

USGS Water Data Discovery

   What are you looking for?

The National Water Information System (NWIS) is the Nation's principal repository of water resources data. It includes data from more than 1.5 million sites, some in operation for more than 100 years. Most NWIS data can be accessed directly at:
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 try contacting a local USGS Water Science Center.

Water Now

WaterNow@usgs.gov How can I quickly get current water conditions that are important to me, such as water levels, streamflow, or temperatures? How do I find locations where these data are available?

WaterAlert How can I be alerted to water conditions that exceed thresholds that are important to me, such as high water levels or temperatures? How do I find locations where these alerts may be available?

Real-time streamflow
Real-Time Streamflow Where is the USGS collecting and transmitting real-time streamflow data right now? How does flow today compare with historical streamflow? How can I see these sites on a map and get to the data? (Fact Sheet)

Real-time flood data WaterWatch flood data
Where in the Nation are floods or very high flows occurring now? How can I see these sites on a map and get to the data?

Real-time drought data
WaterWatch drought data Where in the Nation are droughts or very low flows occurring now? How can I see these sites on a map and get to the data?

Real-time groundwater levels the real-time groundwater level network
Where is the USGS collecting and transmitting real-time groundwater levels right now? How do levels today compare with historical levels? How can I see these sites on a map and get to the data?

Recent groundwater levels
the Active Water-Level Network Where in the Nation is the USGS currently collecting groundwater level data? How can I see these sites on a map and get to the data? Data shown on these maps may be as recent as a few minutes old or may be from as long as a year ago.

Groundwater response to climate
the Climate Response Network Where are the wells that are highly sensitive to climate variations where the USGS is currently collecting groundwater level data? What are the long-term and short-term trends in water levels?
How can I see these sites on a map and get to the data? (Fact Sheet)

Real-time surface water quality
Water Quality Watch Where is the USGS collecting and transmitting real-time water quality data? How do levels today compare with historical levels? These data are limited to measurable characteristics such as temperature, turbidity, specific conductance (salinity), dissolved oxygen and pH (acidity).
How can I see these sites on a map and get to the data?

American Whitewater I want to find streamflow or water-level data that will tell me if a particular river will be suitable for rafting, kayaking, or fishing today.

General recreation information can be found at www.recreation.gov

Private organizations such as American Whitewater provide alternative resources that use USGS and other information for planning water-based activities.

Water Then

Annual water data reports
the WDR Mapper Can I see all of the locations where the USGS has published water resources data for a particular year? How can I see these sites on a map and get to the data?

Instantaneous streamflow data
(prior to 2007)

the Instantaneous Data Archive I want to find long-term streamflow data reported in short time intervals (such as 15 minutes or 1 hour) rather than as daily averages. Where can I see a list of those sites and get to the data?

National Water Quality Assessment the NAWQA Network
The NAWQA program provides a search to physical, chemical, and sediment data that have been collected as part of the national program. (Fact Sheet)

BioData - Aquatic Bioassessment Data for the Nation
USGS BioData The USGS BioData Retrieval system provides public access to aquatic bioassessment data (biological community and physical habitat data) collected by USGS scientists from stream ecosystems across the nation.

Water use in the United States
USGS water-use data Use of water in the United States is tracked by USGS in cooperation with state, tribal, and local governments.


Some notable collections of USGS water data

Sediment data collection.

Sediment data collected by USGS is stored in NWIS and is also described in a dedicated web page and report.

A Reservoir Sedimentation Database from federal agencies is also maintained by USGS.

Hydro-Climatic Data Network collection.

The Hydro-Climatic Data Network 2009 (HCDN-2009) is an updated listing of streamgaging stations where discharge primarily reflects prevailing meteorological conditions. The purpose of the network is to provide a streamflow data set suitable for analyzing hydrologic variations and trends in a climatic context. 

National Stream Quality Accounting Network collection.

The National Stream Quality Accounting Network provides ongoing characterization of the concentrations and transport of sediment and chemicals in the Nation's largest rivers.

National Atmospheric Deposition Program collection.

USGS is the lead federal agency for monitoring of acid rain and related issues as part of the National Atmospheric Deposition Program.

Click on the Principal Aquifer Map and you can view the report, Estimated Withdrawals from Principal Aquifers in the United States, 2000.

The groundwater Atlas and National Atlas provide many maps that summarize water resources data and related information.

Water Tomorrow

USGS collects most of the water data in the Nation, but official forecasts are made by other agencies. Forecasts are subject to any limitations and disclaimers made by the issuing agencies. In all cases, professionals should always be consulted concerning decisions that may affect safety of people or property or economic risk.


Water-resources planning and forecasts are done by other federal, regional, state, local, and tribal agencies. In most cases, USGS partners with these agencies to provide reliable current and historical water data that are essential for making accurate forecasts. These links leave the USGS web sites.

The National Weather Service is the primary federal agency for water resources forecasting, including:


USGS water data and statistics are used by other agencies to estimate future conditions and to assess risks such as flooding and drought. Planners and engineers use USGS water data, statistics, and other data for design of systems for water supply, flood control, environmental protection, and recreation.

USGS Streamgage Statistics Streamflow statistics at USGS gages
Where can I find an analysis of long-term flow statistics for USGS streamgages?

WaterWatch provides basic flow statistics computed from daily streamflow values, including the daily average, minimum, and maximum streamflow; and flow duration curve for the period of observed data.

Additional statistics are computed from daily streamflow values, flood peak flows, and measured low flows, and include, for example, 100-year flood; 7-day, 10-year low flow; and mean annual flow. Statistics such as these are commonly used to help estimate reliability of water supplies and risks of floods or droughts, and may be available in published reports or from StreamStats. However, all flow statistics will vary over time due to extreme floods or droughts, so a local USGS Water Science Center should always be contacted for up-to-date information.

National Streamflow Statistics


Status map of StreamStats installations

Estimate streamflow statistics anywhere
Where can I obtain estimates of streamflow statistics for locations where USGS streamgages are not operated?

National Streamflow Statistics is a downloadable computer program that requires user input of drainage area and other watershed characteristics. Statistics that are available vary among states. (Fact Sheet)

StreamStats provides tools to estimate required inputs for the National Streamflow Statistics computer program, and is currently available for about half of states, with additional states being added regularly. (Fact Sheet)


USGS Home Water Climate Change Science Systems Ecosystems Energy, Minerals, & Env. Health Hazards USGS Intranet

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://water.usgs.gov/data/
Page Contact Information: Water Webserver Team
Page Last Modified: Thursday, 15-Dec-2016 09:02:42 EST