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Water Quality Data (WQX)

Water monitoring data are made available using the Water Quality eXchange (WQX) and maintained in the STOrage and RETrieval (STORET) data warehouse.

Basic Information

Water quality monitoring is a crucial aspect to protecting water resources. Under the Clean Water Act, state, tribal and federal agencies must monitor lakes, streams, rivers and other types of water bodies to determine water quality condition. The data generated from these monitoring activities help water resource managers know where pollution problems exist, where to focus pollution control energies and where progress has been made.

  • WQX is a common format to share water quality data.
  • STORET is a data repository for sharing and storing water quality data.
  • Water Quality Portal is the nation's largest source for water quality data.

The EPA created the Storage and Retrieval (STORET) database to provide a public repository of water quality data. With the use of the Water Quality Exchange (WQX) data format, data are now easily shared with 400 federal, state, tribal and other partners through the Water Quality Portal as a single access point for over 300 million water quality data records.

Water Quality Data Download

Water quality data submitted from over 400 federal, state and tribal agencies, watershed organizations and other groups are available to support your water quality analyses. Water quality data includes physical, chemical, biological, habitat, metrics and indexes data. Data can be retrieved using multiple formats to meet your needs:

Water Quality Portal

The Water Quality Portal (WQP) is a cooperative service sponsored by the United States Geological Survey (USGS), the Environmental Protection Agency (EPA) and the National Water Quality Monitoring Council (NWQMC). It serves over 300 million water result records from EPA STORET, the USGS National Water Information System (NWIS) and the U.S. Department of Agriculture Sustaining the Earth's Watersheds, Agricultural Research Data System (STEWARDS).

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STORET Warehouse

The STORET Warehouse contains water quality data submitted after 1/1/1999. Most of the data in STORET is now available through the Water Quality Portal, with exception to habitat data. We are working to make all data in STORET available through the Portal.

STORET Information:

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Legacy Data

The LDC (Legacy Data Center) contains historical water quality data dating back to the early part of the 20th century and collected up to the end of 1998. Data is no longer being placed in the Legacy Data Center, but the public can still access data from it, either from flat files, or query tools. Please visit the LDC page for more information or to download data.

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The STORET mapping service provides three end points. One mapping service provides access to the raw data in the warehouse (non-indexed - aka no reach/measure) and the other two mapping services provide access to the indexed data stored in WATERS/RAD with the release of NHDPlus v2.1 which is based on a snapshot of data in the warehouse at a particular point in time.

  • Geospatial Data Downloads

    • State and Watershed Geospatial Data
    • National Geospatial Datasets
    • ATTAINS Program
    • Impaired Waters with TMDLs
    • BEACH Program
    • Water Quality Standards Program
    • 303(c) Water Quality Standards

    Geospatial data for EPA’s Office of Water Programs, including 303(d) Impaired Waters, 305(b) Assessed Waters and Total Maximum Daily Loads (TMDLs) are available for download by state or watershed, as well as at a national extent. Generally, state-level geospatial data represents the most recent data submitted to EPA by states. EPA provides WATERS geospatial data in a variety of formats including Geographical Information Systems (GIS) compatible shapefiles and geodatabases, as well as both vector and raster keyhole markup language (KML) and KMZ files for viewing WATERS data in Google Earth.


Water Quality Data Upload with WQX

There are two options for you to share your data using WQX. You can choose a standard web-based application (WQX Web) that uses Microsoft Excel spreadsheets or you can choose to create a custom submission application using WQX XML schema through Exchange Network Nodes or Node Clients. 

The approach which is best for your organization depends on your technical expertise, data volume and resources. The WQX Web application requires less technical expertise and requires manual steps to upload. Custom WQX XML submission applications may be more efficient for organizations data with larger databases and automated submissions.

Standard Upload Resources

What is WQX Web?
WQX Web is a Microsoft Excel based tool to share data in a common format.

How do I prepare my data for WQX Web?
WQX Web enables data owners to share physical, chemical, biological, habitat, index, and metrics data.  Data is formatted into rows and columns that contain the information or metadata supporting the data result, including: where was it collected, when was it collected, how was it analyzed, and other description fields.

How do I ensure a good data file?
Good data quality ensures that your data can be reused by another user for analysis. The documents below will help you improve the quality of your data.

How do I send my data?
To send your data, you must register with EPA and create a user account. Once you create an account, you will establish an “Import Configuration” that will enable you to upload your file.

  • Follow the steps outlined in the WQX Web Registration Guide (42p, 3M)
  • For users who are already registered, you can access WQX Web directly via CDX Login page
  • WQX Web Registration and Submission Videos -  Coming Soon

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Custom Upload

Data owners can establish a custom data flow using WQX XML schema and share their water quality data via the Exchange Network.

Data owners may find these domain value services helpful when preparing their data sets.

  • WQX Domain Values  tables provide data elements to assist data owners and users in conforming to a consistent nomenclature and can be queried to determine the EPA-supplied values.  

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Learn More

General Information

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Training Videos

  • WQX Web Videos - Coming Soon  

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User Community

  • User Call - The STORET Team usually hosts a call on the 4th Thursday of each month, from 12-1 EST, to inform the user community of new updates since the previous call.  You can view the monthly user call notes at:  Monthly Conference Call Notes
  • List Serve - To be notified of user calls and water data updates, sign up for our List serve by sending a blank email to To unsubscribe, send another blank email to
  • Help Desk Support - The user help desk is available for any STORET, WQX and Water Quality Portal related issues or questions. To access the help desk, please contact us at: 1-800-424-9067 or 
  • Regional Coordinators - EPA Regional Staff who are knowledgable on STORET and WQX 
  • User-Created Tools and Applications - List of third-party tools and applications developed by members of the STORET/ WQX user community

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