An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Toxic-Impaired Waterbodies on 303d Lists in the Columbia River Basin

This report is intended for use by the Columbia River Basin Restoration Working Group members and other entities working to understand and reduce toxics in the Columbia River Basin.

Waterbodies listed as impaired for toxic pollutants can serve as a starting point for prioritizing restoration and management actions and the absence of waterbodies on 303(d) lists can help identify data gaps to inform future monitoring and assessment efforts. This report:

  • Identifies the more than 50 toxic contaminants that are on 303(d) lists of impaired waters in the Columbia River Basin.
  • Summarizes the location of impaired waters for ten toxic contaminants.
  • Provides links to EPA-approved TMDLs and implementation plans.

For questions, please contact David Gruen (

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.