Water Quality Mapping Center

image of mapThe Water Quality Mapping Center provides access to information on Maryland's surface water quality in a geographic format. The links provided (from General Information to Maryland's Shellfish Harvesting and Closure Information) were designed to make water quality GIS information more widely available to those without specialized software. Advanced Users who would like to download particular geographic datasets should also click on the map links. Once on the map page users can click a link to download GIS data.  

Click on one of the links below to access information specific to the Designated Use Classes, Integrated Report (water quality impairments), Tier II high quality waters, or Shellfish Harvesting Area Closure information.  Note: No special software is needed for the map pages.  However, maps will load faster using the latest version browsers (e.g. Internet Explorer 9 or later, Google Chrome). 

For guidance on using the maps, please watch the on-line video tutorial.  Reminder: Please make sure that your speakers are turned on. 

General Information

  • Find My Watershed - This map was designed to help individuals find out what watershed they live in or what watershed their project affects.

Designated Uses and Use Class Information

Water Quality Assessment Information - Integrated Report

TMDL Information

  • TMDL Maps - This page includes links to a series of maps for each pollutant that has had a TMDL completed.  The purpose of these maps is to provide information to help with implementing TMDLs.
  • Information about TMDLs

Tier II High Quality Waters

Maryland's Shellfish Harvesting and Closure Information

Contact Information

For questions or comments concerning this page please call 410-537-3572.​​