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Water Quality Assessment Program

Every two years, Oregon DEQ is required to assess water quality and report to the U.S. Environmental Protection Agency on the condition of Oregon's waters. DEQ prepares an Integrated Report that meets the requirements of the federal Clean Water Act for Sections 305(b) and 303(d).

  • Section 305(b) requires a report on the overall condition of Oregon's waters.
  • Section 303(d) requires identifying waters that do not meet water quality standards and where a Total Maximum Daily Load pollutant load limit needs to be developed.

The Integrated Report includes an assessment of each water body where data are available, and the list of waters identified under Section 303(d) as water quality limited and needing a TMDL. Waters may be added to the 303(d) list based on evaluation of new data, application of new or revised water quality standards, or information showing water quality has declined. Waters may be removed from the 303(d) list when TMDLs or other control measures have been established that are expected to improve water quality, when data show water quality has improved, and in some cases when water quality standards are revised.

DEQ reports to the EPA the status of our waters, and those waters which belong on the 303(d) list. The EPA displays this data for the nation on How’s My Waterway?

 Current News
  • EPA approves Oregon's 2022 Integrated Report
  • DEQ's blog post on the 2022 Integrated Report
  • DEQ has convened Scientific Technical Workgroup for Ocean Acidification and Hypoxia 
  • DEQ will release the 2024 Draft Assessment Methodology for public comment in January 2023
  • DEQ will conduct the 2024 Call for Data in February 2023

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Water Quality Assessment staff contacts:

Lesley Merrick: Program Lead
Travis Pritchard: Assessment and Data Specialist
Daniel Brown: Laboratory Data Lead

Connie Dou: Water Quality Standards and Assessments Manager