Maryland's Designated Uses/Use Class Map


About the Map

Maryland’s Designated Uses/Use Class map was updated in January 2019 and is consistent with the downloadable geodatabase provided below. The map displays the use classes assigned to Maryland's surface waters (rivers, impoundments, and tidal 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.

This map also shows waters with cold or cool water existing uses that have underwent public review.  For these waters, data have shown cold water obligates being supported and oftentimes cooler water temperatures than what are required by the currently designated use and criteria.  These waters must be protected so as to maintain these cold water existing uses.  For more information about Maryland’s existing uses please visit the “Existing Use Determinations​” webpage.  

Please note that this map is a representation of the use classes in Section Users should use these files for informational purposes only and not as the legally defined boundaries for each use class. It is recommended that you consult COMAR to determine the extent of the use classes. To access COMAR Section, please click here.

GIS Download

The geodatabase accessible below was produced with ESRI's ArcGIS software. 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. Click "Download Geodatabase” below for a zip file containing the geodatabase that delineates use classes for the following water body types (updated as of January 2019):

  • ​Impoundments
  • Rivers and Streams
  • Tidal Waters

Download Maryland’s Designated Use Class Geodatabase

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

Contact Information

Please direct questions or comments con​cerning Maryland's water quality standards to Melinda Cutler at

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