Water Quality

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).

  • CWA Section 305(b) requires a report on the overall condition of Oregon's waters.
  • CWA 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.

Oregon's 2012 Integrated Report and 303(d) List - Effective; EPA additions pending

DEQ submitted Oregon's 2012 Integrated Report and 303(d) list to EPA in November 2014. (See links to Oregon’s 2012 Integrated Report and 2012 Assessment Database and 303(d) list below.)

EPA approved most of the submitted 303(d) listings and delistings on Dec. 21, 2016. The approved 2012 303(d) list is currently effective for Clean Water Act purposes.

At the same time, EPA disapproved DEQ’s submittal for not including other waters. EPA proposed adding other waters to Oregon’s 303(d) list and is taking public comments on the proposed additions until Feb. 6, 2017. See EPA Action Oregon 2012 303(d) List for information on the proposed additions and how to provide comments to EPA.

*A TMDL (Total Maximum Daily Load) is the calculated amount of pollutant a water body can receive and still meet Oregon water quality standards.