The National Ground-Water Monitoring Network (NGWMN) is a compilation of selected wells monitoring groundwater aquifers all around the nation. The NGWMN Data Portal brings groundwater data together in one place to provide users with current and reliable information for the planning, management, and development of groundwater resources.

About the Network


The NGWMN network is sponsored by the Advisory Committee on Water Information's (ACWI) Subcommittee on Ground Water (SOGW) and was established in 2009 with a pilot network.

The goal of the National Ground-Water Monitoring Network (NGWMN) is to provide information needed for planning, management, and development of groundwater supplies to meet current and future water needs and ecosystem requirements. This will be accomplished by aggregating suitable groundwater data from local, State, and Federal organizations. A consensus-based framework document ( was developed to provide guidance to ensure that the data are comparable and can be included in a nationally consistent network. The framework design focuses on providing information needed to assess the quantity of groundwater reserves as constrained by quality. The scale of the network focuses on Principal and Major Aquifers of the United States.

Network Design

The network is composed of selected wells from existing Federal, multi-state, State, Tribal, and local groundwater monitoring networks. The focus of the NGWMN is on water levels and water quality in Principal and Major Aquifers of the United States. Well classification subnetworks and monitoring categories are defined in the framework document ( and are briefly described here:

Well Classification Subnetworks:

Wells in the NGWMN will be designated as being in one of three subnetworks. These are 1) the Background subnetwork, 2) the Suspected Changes subnetwork, and 3) the Documented Changes subnetwork.

Background subnetwork:

Monitoring points that provide data from aquifers or parts of aquifers with no (or minimal) anthropogenic effects. These are from areas that have been minimally affected by human activities and are expected to remain so.

Suspected Changes subnetwork:

Monitoring points that provide data from aquifers or parts of aquifers that may have been affected by man's activity, but that is not documented or conclusive. These wells may also be in areas where changes are anticipated. These may be areas with withdrawals are occurring or where land-use has changed, but the effect has not yet been clearly identified.

Documented Changes subnetwork:

Monitoring points that provide data from aquifers that have documented anthropogenic effects.
The aquifers may:
(1) be known to be heavily pumped
(2) have experienced substantial recharge-altering land-use changes
(3) have managed groundwater resources
(4) are known to have degraded water quality or declining water levels

Baseline Process:

The baseline process is required of all wells to provide or identify an initial monitoring record that is used to place the well into one of the above subnetworks. Five years of monitoring is generally considered adequate to establish these conditions. For existing wells, past data may be used to categorize wells into one of the subnetworks.

Monitoring Categories:

Wells within each subnetwork (Background, Suspected Changes, or Documented Changes) will be assigned to a monitoring category depending on the purpose of the monitoring at the well. These categories, and conditions at the wells, will be used to determine suggested monitoring frequencies.


Trend wells are generally monitored to determine changes over time. The frequency of monitoring depends on the hydrologic conditions of the aquifer and can range from daily data to annual measurements. A subset of the trend monitoring wells will be designated as the "backbone" wells of the NGWMN.


Surveillance monitoring would be used in conjunction with Trend monitoring to periodically report on the overall water-level and water-quality conditions, or status, of the Nation's groundwater resources. NGWMN Surveillance monitoring can be thought of as a periodic "census" of groundwater level and quality. An overall snapshot of groundwater conditions in an aquifer is obtained with Surveillance monitoring. The frequency of Surveillance monitoring generally is much less than Trend monitoring.

Special Studies:

Special studies monitoring is a secondary aspect of the NGWMN. This monitoring is not required and is only provided as an option. Special studies monitoring would be most often associated with the Suspected or Documented Changes Subnetworks and would be used to evaluate the status of ground-water resources at risk, or potential risk, from depletion or impairment. The monitoring frequency would vary, depending on the study. Categorizing wells as special studies acts as a flag to indicate that additional information might be available because wells are measured or sampled for a special purpose regionally or nationally (for example, wells measured to observe the effects of hydraulic fracturing).

Network Status

A pilot phase that started in 2009 initially populated the network with data from 5 pilot networks. These pilots were: the Mahomet-Teays aquifer in Illinois and Indiana, the Cambrian-Ordovician aquifer in southeastern Minnesota, and Principal and Major Aquifers in Montana, New Jersey, and Texas.

Following the pilot phase, additional USGS water-level monitoring wells that met the network criteria were added to the NGWMN for some states. In 2015, the Network received funding and began implementation. Eleven agencies were funded to become data providers or to complete work necessary to become a data provider beginning in 2015 or early 2016. These projects are now complete and data connections have been established to all of these agencies data. These states are Delaware, Kansas, Mississippi, North Carolina, Oklahoma, Oregon, South Carolina, and Utah. Data for all these states is currently being served through the Portal. Data for Mississippi is in the process of being added to the Portal and should be available soon. Descriptions of work done in these projects are available  here.

In late 2015 the Network began the process of funding data providers through cooperative agreements. Current information about the cooperative agreements is availablehere.  

The Program Board is proposed in the NGWMN Framework Document to provide input into the NGWMN scope and direction and to assist with the evaluation of proposals for funding. The National Ground-Water Monitoring Network Program Board was established in 2015 to assist with evaluating proposals submitted for competitive cooperative agreements. The Program Board is composed of up to ten members. Six of these members are to represent NGWMN data provider agencies. The remaining members are Federal representatives and subject matter experts. Information on the structure and membership of the Program Board are available in the NGWMN Program Board Operating Principles.

The USGS National Ground-Water Monitoring Network (NGWMN) offered two competitive funding opportunities for the NGWMN in FY 2016. Funds were available to new data providers to select and classify sites within existing monitoring programs, to set up web services that will link the data to the NGWMN Portal, and to produce a report describing this process. Funds were available to existing data providers to maintain web services and keep site information current. Existing data providers could also receive funding to collect data to improve site information, to maintain wells, and to drill new or replacement Network wells. The projects awarded in both rounds of funding in 2016 are described in this document

The latest round of cooperative agreements is for Fiscal Year 2017. This opportunity closed in January 2017 and awards for this funding opportunity are pending.


The Data Portal

The Data Portal

The NGWMN Data Portal is the access point for information about the wells in this network and for their related lithology (geology), construction, water-level and water-quality data. To access the portal click here. To learn how to use the portal click here.

An important aspect of the NGWMN Data Portal is that it is not an aggregated database of data from all participants, but is a gateway to the data which are maintained and served by each participating organization. Original data are retrieved from each data provider by the portal in real-time.

The Data Portal has filters and map-based selection capabilities that allow the user to select the sites of interest. After the sites are selected, requests are sent to the contributing databases serving the selected sites to obtain the data. These data are then returned via the portal in graphs and tables and can also be downloaded for later use.

Queries can be made on network type (Water Level or Water Quality), well classification, and monitoring category. Sites can also be queried based on Principal Aquifer, type of data available, contributing agency, and state/county.

Disclaimer: Please note that this is a beta version of the NGWMN Data Portal, which is still undergoing development and testing. Should you encounter any bugs, glitches, lack of functionality or other problems, please contact the site administrator immediately so they can rectify these accordingly. Your help in this regard is greatly appreciated. All information published herein is gathered from sources which are thought to be reliable, but the user should not assume that the information is official or final. The NGWMN Data Portal does not assume responsibility for errors, and all information is subject to change without notice.

Web Services

Web service requests may be submitted to obtain data directly and to bypass the NGWMN map interface. Currently only basic site information and water levels are available through web service requests. For full site information, lithology, construction information or water quality data visit the NGWMN Data Portal. For more information on the  NGWMN Web Services, see the Web Services Guide.


Booth, N.L., Brodaric, B., Lucido, J.M., Kuo, I.-L., Boisvert, E., and Cunningham, W.L., 2011, Development of an Interoperable Groundwater Data Exchange Network between the United States and Canada, in GeoHydro 2011 Conference Proceedings Paper. URL:

Blodgett, D., Read, E., Lucido, J., Slawecki, T., and Young, D., 2016, An Analysis of Water Data Systems to Inform the Open Water Data Initiative: JAWRA Journal of the American Water Resources Association, v. 52, no. 4, p. 845-858. DOI:10.1111/1752-1688.12417

Larsen, S., Hamilton, S., Lucido, J., Garner, B., and Young, D., 2016, Supporting Diverse Data Providers in the Open Water Data Initiative: Communicating Water Data Quality and Fitness of Use: JAWRA Journal of the American Water Resources Association, v. 52, no. 4, p. 859-872. DOI:10.1111/1752-1688.12406

Blodgett, D., Lucido, J., and Kreft, J., 2015, Progress on water data integration and distribution: a summary of select U.S. Geological Survey data systems: Journal of Hydroinformatics, v. 18, no. 2, p. 226-237. DOI:10.2166/hydro.2015.067

Brodaric, B., Booth, N., Boisvert, E., and Lucido, J., 2015, Groundwater data network interoperability: Journal of Hydroinformatics, v. 18, no. 2, p. 210-225. DOI:10.2166/hydro.2015.242


Data Providers

Current Data Providers

The  National Ground-Water Monitoring Network (NGWMN) is a compilation of selected groundwater monitoring wells from Federal, State, and local groundwater monitoring networks across the nation. The following agencies are currently contributing to the NGWMN.

The agencies listed below are currently providing data to the NGWMN. 

Alaska Department of Natural Resources -Pending final report

Arizona Department of Water Resources

Colorado Department of Water Resources -Pending final report

Delaware Geological Survey

Illinois State Water Survey

Indiana Geological Survey -Pending final report

Iowa Department of Natural Resources

Iowa Geological Survey

Kansas Geological Survey

Maine Geological Survey

Minnesota Department of Natural Resources

Minnesota Pollution Control Agency

Mississippi Department of Environmental Quality

Montana Bureau of Mines and Geology

Nebraska, Conservation and Survey Division

New Hampshire Geological Survey

New Mexico Institute of Mining and Technology

North Carolina Department of Environmental Quality

Oklahoma Water Resources Board

Oregon Water Resources Department

South Carolina Department of Natural Resources

Texas Water Development Board

U.S. Geological Survey

Utah Geological Survey

Washington State Department of Ecology

Wyoming Department of Environmental Quality -Pending final report

Pending Data Providers

The following agencies are in the process of becoming a data provider to the NGWMN:

Geological Survey of Alabama

Florida Department of Environmental Protection

Nebraska Department of Environmental Quality

Water Replenishment District of Southern California

Washington State Department of Natural Resources

Resources for New Data Providers

Information about USGS cooperative agreements to fund data providers is available here.

The National Ground-Water Monitoring Network focuses on Principal Aquifers. Principal Aquifers are defined by the USGS in the Ground Water Atlas.

Tip Sheets:

Tip Sheet on Well Selection Criteria for Water Levels 

Tip Sheet on Well Selection Criteria for Water Quality

Tip Sheet on Defining the "Subnetwork"

Tip Sheet on Defining Monitoring Categories 

Tip Sheet on Populating the Well Registry

Tip Sheet on Minimum Data Requirements for Candidate Sites

Tip Sheet on Web Service Development

Tip Sheet on Standard Elements for Water-Quality web services

NGWMN Data Dictionary

Other Resources:

A spreadsheet showing the suggested density of water-level and water-quality sites by state and Principal aquifer is available here.

The NGWMN Well Registry Management System can be accessed here. If you are a USGS employee, you can access it here.

Get Involved

The  NGWMN is actively seeking data providers for the Network. Data providers work with the USGS to set up connections between their databases and the NGWMN Data Portal to pass data to the Network as needed. The data providers also work with the USGS to select and classify wells for the Network.

Information on a funding opportunity available to assist state or local water-resource agencies in becoming data providers is available here. Other federal, tribal, educational, or private agencies or organizations which have groundwater data to contribute can also become a part of the Network. Contact the ACWI Subcommittee on Ground Water (SOGW) to find out about becoming a data provider.