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About STORET and WQX

Water quality monitoring is a crucial aspect to protecting water resources. State, Tribal, and Federal agencies must monitor lakes, streams, rivers, and other types of water bodies to assist them in determining water quality condition. From these monitoring activities, water quality monitoring data is generated. Without this data, water resource managers cannot know where pollution problems exist, where we need to focus our pollution control energies, or where we've made progress.

The STORET Data Warehouse


The STORET Data Warehouse is EPA's repository of the water quality monitoring data collected by water resource management groups across the country. These organizations, including states, tribes, watershed groups, other federal agencies, volunteer groups and universities, submit data to the STORET Warehouse in order to make their data publically accessible. Data can then be re-used for analysis. WQX is the framework by which organizations submit data to the Warehouse, and more information about WQX is below.
To download STORET data Click Here Data Download
(For assistance please contact the STORET helpdesk at STORET@epa.gov).

Data in the STORET Warehouse are of documented quality, meaning that a certain level of metadata, including where, how, why, when and what was monitored must be included with all data submissions. Each sampling result in the STORET Warehouse is accompanied by information on where the sample was taken (latitude, longitude, state, county, Hydrologic Unit Code and a brief site identification), when the sample was gathered, the medium sampled (e.g., water, sediment, fish tissue), and the name of the organization that sponsored the monitoring. In addition, the STORET Warehouse contains information on why the data were gathered; sampling and analytical methods used; the laboratory used to analyze the samples; the quality control checks used when sampling, handling the samples, and analyzing the data; and the personnel responsible for the data. Please visit the STORET/ WQX concepts page to learn more about the vocabulary used in the system to describe water quality monitoring samples.

The EPA does not change or filter incoming data. This means that when pulling data out of the Warehouse, users must be aware that they are responsible for screening the data for their use.

Specific examples of the types of data that the STORET Data Warehouse contains include:

  • Chemical parameter measurements made in the field or lab
  • Physical parameter measurements such as water temperature or pH
  • Biological sampling results
  • Habitat assessments or observations

Data in the STORET Warehouse can be accessed through the web, either through the STORET Warehouse query application, or through more automated web services.

Water Quality Exchange

WQX logo

Groups submit data to the STORET Data Warehouse through a framework called the Water Quality Exchange, or WQX. WQX is not a distributed database that people use, but rather a standard way of sharing data to the STORET Data Warehouse, using the National Environmental Information Exchange Network.

The WQX framework consists of different pieces. First, WQX defines a standard set of data elements that must be captured in a data submission file in order for the data to come into the STORET Data Warehouse. Second, WQX uses a standard set of internet protocols that define how a data submission is made to the EPA. Please go to the WQX page for more information about how WQX works.

The STORET Legacy Data Center

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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