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Water Quality Assessment Program

Every two years, 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, or TMDL, 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 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

April 2024: DEQ released the draft 2024 Integrated Report for public comment on April 16, 2024 (should this be 18?) and a final 2024 Assessment Methodology [final? – link to new version]. Visit the 2024 Integrated Report page for complete information.

Older updates

  • May 2023: DEQ released a draft Assessment Methodology to the impacts of Ocean Acidification and Hypoxia in state marine waters in May 2023
  • January 2023: DEQ released the 2024 Draft Assessment Methodology for public comment in January 2023. View the 2024 Call for Data page [link to the page] for more information.

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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, Source Water Protection and Assessments Manager