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Water Quality Assessment Program

DEQ's 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?

May 2026 

  • DEQ Released the Draft 2026 Integrated Report for public comment on May 18, 2026
    • The proposed methodology for developing the 2026 Integrated Report, officially referred to as the Draft Assessment Methodology was open for public comment from March 25 to May 27, 2025.  
    • An open call for data that may be used as part of the 2026 Integrated Report was open from March 25 to May 27, 2025.
    • Presentation to the Environmental Quality Commission on the 2026 Assessment Methodology updates was given on Sept. 11, 2025. 
  • EPA Approved the 2024 Integrated Report on May 12, 2026. Visit the EPA Approved Integrated Report page for complete information.

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Contact

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