Water Quality Standards Regulations: Washington

Presented are water quality standards in effect for Clean Water Act (CWA) purposes for this state.

EPA is posting these standards as a convenience to users and has made a reasonable effort to assure their accuracy. For each document listed under "State Standards in Effect for CWA Purposes", EPA has made a reasonable effort to identify parts of the standards that are disapproved or are otherwise not in effect for CWA purposes. Additionally, please note the documents may also contain provisions that EPA does not have the authority and duty to act on under the Clean Water Act because the provisions are not water quality standards.

What is a New or Revised Water Quality Standard Under CWA 303(c)(3)? - Frequently Asked Questions (pdf) (108.04 KB)

On this page:

State Standards in Effect for CWA Purposes
Federally Proposed or Promulgated Standards

State Standards in Effect for CWA Purposes

In general, WQS submitted by a state, authorized tribe, or territory are not effective for Clean Water Act purposes until EPA reviews and approves them. The Actions Summary Tables summarize approval (and disapproval) actions for this state’s WQS and contain EPA action letters that identify which WQS are in effect for CWA purposes. For provisions on which EPA has not taken action, please refer to the related action letter.

Water Quality Standards for Surface Waters of the State of Washington, Chapter 173-201A WAC (pdf) (3.87 MB)
(Effective November 19, 2021)
Sediment Management Standards, Chapter 173-204 (pdf) (1.06 MB)
(Effective December 18, 2015)
Waters Requiring Supplemental Spawning and Incubation Protection for Salmonid Species (2011) (pdf) (9.38 MB)

Action Summary Table on Washington’s Water Quality Standards

Date of EPA Action	Summary of EPA Action	Notes on the Action	Other Related Information
11/19/2021	Disapproved WQS Natural and irreversible human conditions Allowable human contribution to natural conditions provisions for aquatic life temperature Allowable human contribution to natural conditions provisions for aquatic life dissolved oxygen Refer to Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 11/19/2021 (pdf) (287.77 KB)	On February 10, 2014, the Northwest Environmental Advocates filed a complaint in U.S. District Court for the Western District of Washington challenging, in part, EPA’s February 11, 2008 CWA section 303(c) approval of the natural conditions provisions. On October 17, 2018, the Court issued an Order Granting a Stay (Dkt. 95) pending EPA’s reconsideration of its prior determinations. EPA’s 11/19/2021 action details the results of that reconsideration.
09/30/2021	Approved WQS Non substantive changes to Short Term Modifications Disapproved WQS Revisions to fresh water temperature guidelines Revisions to marine water temperature guidelines Revisions to short term modifications Refer to Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 09/30/2021 (pdf) (299.59 KB)		Please refer to the action letter for provisions on which EPA did not take action because they are not new or revised water quality standards.
10/13/2020	Approved WQS Shellfish harvesting bacteria criteria averaging period Disapproved WQS Shellfish harvesting bacteria criteria (unconditional shellfish harvest) Refer to Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 10/13/2020 (pdf) (241.84 KB)		Please refer to the action letter for provisions on which EPA did not take action because they are not new or revised water quality standards.
09/30/2020	Approved WQS Revised compliance schedule provision pertaining to aquatic life uses Refer to Action Letter for Details EPA Action Letter dated 09/30/2020 (pdf) (179.67 KB)		Please refer to the action letter for provisions on which EPA did not take action because they are not new or revised water quality standards.
03/05/2020	Approved WQS Aquatic life total dissolved gas criteria in fresh waters for the Snake and Columbia Rivers. Marine water aquatic life use designation categories. Table 240 footnote dd. Use designations—Marine waters. Refer to Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 03/05/2020 (pdf) (335.51 KB)
5/10/2019	Approved WQS Certain human health criteria (HHC) [excluding arsenic] that EPA previously disapproved on 11/15/2016, in part. Refer to Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 5/10/19 (pdf) (838.86 KB) Note: If you need assistance with the above document, call Hanh Shaw at 206-553-0171.	On November 15, 2016, EPA partially approved and partially disapproved certain HHC that the Washington Department of Ecology submitted to EPA for review on August 1, 2016. In response to a February 21, 2017 petition from several entities, EPA has reconsidered its partial disapproval.	In light of this decision, EPA intends to initiate a notice and comment process at a later date on a separate proposal to withdraw the related federally promulgated HHC.
04/30/2019	Approved WQS Recreational use criteria for fresh and marine water quality recreational uses Updated water contact use categories Refer to Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 04/30/2019 (pdf) (727.76 KB)	On April 30, 2019, the Washington Department of Ecology adopted new recreational use criteria for fresh and marine water quality recreational uses and updated water contact use categories consistent with EPA’s 304(a) recommendations.
11/15/2016	Approved WQS 45 human health criteria contained in Table 240 Narrative revisions at WAC 173-201A-240, in part Revisions to the variance provision at WAC 173-201A-420, in part Revisions to the compliance schedule provision at WAC 173-201A-510(4), in part Disapproved WQS 143 human health criteria contained in Table 240 and associated footnotes Narrative language at WAC 173-201A-240(3) Part of the variance provision at WAC 173-201A-420(5)(a) Refer to Action Letter for Details EPA Action: Partial Approval and Partial Disapproval of Ecology submission (pdf) (4.07 MB, November 15, 2016)	For the criteria that EPA disapproved, concurrent with this action on Washington’s submittal, EPA finalized a federal rule for Washington containing 144 human health criteria in accordance with CWA section 303(c)(3) and (c)(4) requirements. Applicable, EPA-approved human health criteria are available at 40 CFR 131.45.	Please refer to the action letter for provisions on which EPA has not yet taken action.
08/10/2011	Approved WQS • Minor editorial changes and non-substantive revisions. Refer to Action Letter for Details • EPA Action letter dated 08/10/11 (pdf) (2.54 MB)
05/14/2008	Approved WQS • Provisions addressing turbidity in freshwater and marine water. Refer to Action Letter for Details • EPA Action letter dated 05/14/08 (pdf) (180.68 KB)	This action supersedes the February 11, 2008 decision in which EPA did not take action on revisions to provisions addressing turbidity in freshwater and marine waters.
02/11/2008	Approved WQS Definitions Fresh water aquatic life uses categories Fresh water temperature, dissolved oxygen, turbidity, total dissolved gas, and pH criteria Marine water aquatic life uses categories Marine water temperature, dissolved oxygen, turbidity, and pH criteria Shellfish harvesting use and criteria Recreational uses and criteria, marine water Miscellaneous uses, marine water Toxic Substances Natural conditions and other water quality criteria applications Mixing zone policy Short term modification General allowance for compliance schedules Part VI – Use designations for waters of the state Refer to Action Letter for Details • EPA Action letter dated 02/11/08 (pdf) (697.12 KB)
05/23/2007	Approved WQS • Revised marine chronic aquatic life cyanide criterion for waters outside of Puget Sound. Refer to Action Letter for Details • EPA Action letter dated 05/23/07 (pdf) (143.27 KB)
05/2/2007	Approved WQS • New and revised language regarding Washington’s antidegradation policy Refer to Action Letter for Details • EPA Action letter dated 05/02/07 (pdf) (1.1 MB) 05/02/07 ]

Action Summary Table on Washington’s Sediment Management Standards

Date of EPA Action	Summary of EPA Action	Notes on the Action	Other Related Information
12/18/2015	Approved WQS • Various revisions in Parts I-IV of the SMS Refer to Action Letter for Details • EPA Action letter dated 12/18/15 (pdf) (3.15 MB)
09/18/2008	Approved WQS • Various revisions to the SMS, including a new definition, a new section pertaining to marine finfish rearing facilities, and several other revisions to previously existing provisions. Refer to Action Letter for Details EPA Action letter dated 09/18/08 (pdf) (1.89 MB) EPA Action letter dated 04/22/11 (pdf) (496.54 KB)	Decision was re-approved on April 22, 2011 due to litigation.

Date of EPA Action

Summary of EPA Action

Notes on the Action

Other Related Information

12/18/2015

Approved WQS
• Various revisions in Parts I-IV of the SMS

Refer to Action Letter for Details
• EPA Action letter dated 12/18/15 (pdf) (3.15 MB)

09/18/2008

Approved WQS
• Various revisions to the SMS, including a new definition, a new section pertaining to marine finfish rearing facilities, and several other revisions to previously existing provisions.

Refer to Action Letter for Details

EPA Action letter dated 09/18/08 (pdf) (1.89 MB)
EPA Action letter dated 04/22/11 (pdf) (496.54 KB)

Decision was re-approved on April 22, 2011 due to litigation.

Federally Proposed or Promulgated Standards

On November 14, 2022, EPA Administrator Regan signed a rule to restore the protective and science-based federal human health criteria (HHC) for the state of Washington’s waters that EPA had originally promulgated in 2016 but later removed in 2020.
- Federal Human Health Criteria for Washington State Waters
Reconsideration of EPA’s Partial Approval/Partial Disapproval of Washington’s Human Health Water Quality Criteria – EPA approved certain human health criteria that the Agency previously disapproved on November 15, 2016 from an August 1, 2016 Washington standards submission. This action is in response to a February 21, 2017 petition from several entities.
- EPA Action Letter and Technical Support Document dated 5/10/19 (PDF)
  Note: If you need assistance with the above document, call Hanh Shaw at 206-553-0171.
Final Revision of Federal Human Health Criteria Applicable to Washington - EPA revised the federal Clean Water Act human health criteria applicable to waters under Washington’s jurisdiction to ensure that the criteria are set at levels that will adequately protect fish consumers in Washington from exposure to toxic pollutants. Concurrent with EPA’s final rule, EPA took action under the CWA to approve in part, and disapprove in part, human health criteria submitted by Washington.
- Fact Sheet: Revision of Federal Human Health Criteria Applicable to Washington (pdf) (102.11 KB, November 2016, EPA 823-F-16-003)
- Federal Register Notice | Docket OW-2015-0174
  Note: This final rule will be effective on 12/28/16.
- EPA's Partial Approval/Partial Disapproval of Washington's Human Health Water Quality Criteria and Implementation Tools (pdf) (2.16 MB, November 15, 2016)
- Table of Human Health Criteria Effective for Clean Water Act Purposes in Washington (pdf) (202.03 KB)
Proposed Revision of Federal Human Health Criteria Applicable to Washington
- Fact Sheet: Proposed Revision of Federal Human Health Criteria Applicable to Washington (pdf) (91.73 KB, August 2015, EPA 820-F-15-005)
- Federal Register Notice (September 14, 2015)
- Recordings of EPA’s public hearings on the proposed rule:
  - View the Virtual Public Hearing: December 15, 2015
  - View the Virtual Public Hearing: December 16, 2015
- Federal Register Notice Extension of Public Comment Period for the Revision of Certain Federal Water Quality Criteria Applicable to Washington (October 28, 2015)
Withdrawal of Federal Marine Aquatic Life Water Quality Criteria for Toxic Pollutants Applicable to Washington State
- Direct Final Rule: Federal Register Notice (July 09, 2007)
- Proposed Rule: Federal Register Notice (July 09, 2007)
- Docket at Regulations.gov

EPA Contact

Lindsay Guzzo
(206) 553-0268

State Program Information

Washington's Water Quality Standards Program

Modernizing Public Hearings for WQS Reviews

The document suggests how states and authorized tribes can conduct online public hearings in lieu of in-person public hearings, consistent with federal public hearing requirements.

Modernizing Public Hearings for Water Quality Standard Decisions Consistent with 40 CFR 25.5 (pdf)