Maryland's Designated Uses/Use Class Map

Please note that this map contains an error for Tuscarora Creek in Frederick County. As such this map is under revision. Please consult Code of Maryland Regulations for the official stream class designations.

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The map above was last updated in October 2014 and is consistent with the downloadable geodatabase.  Both of these resources require revisions and are provided here only as informational resources.  Please consult Code of Maryland Regulations for the official stream class designations.

About the Map

The map above displays the use classes assigned to Maryland's surface waters as promulgated in Code of Maryland Regulations (COMAR) Section Maryland classifies surface water bodies according to use classes which describe the suite of specific designated uses or goals for that water body. For more information about Maryland's surface water use classes please visit MDE's designated use web page.

Please note that this map is a representation of the use classes in Section and not an exact reflection of the extents. Mapping limitations led to some differences near the boundaries of uses. If your area of interest is near one of these boundaries it is recommended that you consult COMAR to determine the exact extent of the use class. To access COMAR Section, click here

How to Use the Map

To navigate the map, use your arrow to drag and pan. Click the plus and minus buttons to zoom in and out. Enter an address in the window (top right) to zoom to a location. Clicking on "Basemap" allows the user to change the background (e.g. aerial photography, topographic coverage, etc). Clicking on a stream, impoundment/reservoir, or estuarine water body will display the name of the water body, its use class, and watershed information. Clicking on “View Larger Map” will take the user to a customizable map interface where additional layers may be added.

GIS Download

Download Geodatabase

To use the downloadable geodatabase, users must have ESRI's ArcGIS 9.3 or a later version installed on their computer. Users should always consult the metadata included with this geodatabase prior to using it. This geodatabase provides water body names and the designated use classes (e.g. I, II, IV-P, etc) discussed in Code of Maryland Regulations (COMAR) For those waters where an existing use applies, the existing use is provided as well. Please note: In some cases, these GIS files show only the approximate boundaries for the use class. Users should use these files for informational purposes only and not as the legally defined boundaries for each use class. Click "Download Geodatabase" above for a zip file containing the geodatabase that delineates use classes for the following water body types (updated as of July 2014):

  • Impoundments
  • Rivers and Streams
  • Tidal Waters.

For other water quality mapping information, please visit MDE's Water Quality Maps page.

Please direct questions or comments concerning Maryland's water quality standards to Matthew Stover at or 410-537-3611.​