Water Quality Standards Regulations: Washington

EPA Contact

Lindsay Guzzo
(206) 553-0268

State Program
Information

Washington's Water Quality Standards Program

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

The U.S. Environmental Protection Agency 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", the 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 the 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 the EPA reviews and approves them. The Actions Summary Tables summarize approval (and disapproval) actions for this state’s WQS and contain the EPA action letters that identify which WQS are in effect for CWA purposes. The EPA is currently working on ESA consultation for the provisions in which the EPA has not yet acted. This website will be updated after ESA consultation is complete and the EPA takes final action.

Water Quality Standards for Surface Waters of the State of Washington, Chapter 173-201A WAC (pdf) (23.39 MB)
(Effective December 20, 2024)
- WAC 173-201A-240(5)(b), Table 240: Aquatic Life Criteria (pdf) (490.46 KB)
  (Effective December 20, 2024)
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
12/20/2024	Approved WQS 145 human health criteria for 75 pollutants contained in Table 240 Footnote F and portions of footnotes A, C, and E associated with Table 240 Notes on the Action EPA is deferring action on new revisions to Washington's aquatic life criteria in Table 240. The EPA is in the process of evaluating these aquatic life criteria revisions and intends to address them in a subsequent and separate CWA section 303(c) action. Please refer to the action letter for provisions on which the EPA did not take action because they are not new or revised water quality standards. Refer to the Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 12/20/2024 (pdf) (21.23 MB)
3/8/2024	Approved WQS WAC 173-201A-020: Definitions WAC 173-201A-330: Tier III – Protection of outstanding resource waters WAC 173-201A-332: New section and Table 332 – Outstanding resource water designations by water resource inventory area (WRIA) WAC 173-201A-602: Table 602 – Use designations for fresh waters by water resource inventory Notes on the Action Please refer to the action letter for provisions on which the EPA did not take action because they are not new or revised water quality standards. Refer to the Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 03/08/2024 (pdf) (194.86 KB)
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 the Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 11/19/2021 (pdf) (287.77 KB) Notes on the Action 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, the 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 the EPA’s reconsideration of its prior determinations. The 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 the Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 09/30/2021 (pdf) (299.59 KB) Other Related Information Please refer to the action letter for provisions on which the 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 the Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 10/13/2020 (pdf) (241.84 KB) Other Related Information Please refer to the action letter for provisions on which the 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 the Action Letter for Details EPA Action Letter dated 09/30/2020 (pdf) (179.67 KB) Other Related Information Please refer to the action letter for provisions on which the 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 the 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 the EPA previously disapproved on 11/15/2016, in part. Notes on the Action On November 15, 2016, the EPA partially approved and partially disapproved certain HHC that the Washington Department of Ecology submitted to the EPA for review on August 1, 2016. In response to a February 21, 2017 petition from several entities, the EPA has reconsidered its partial disapproval. Refer to the 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.
04/30/2019	Approved WQS Recreational use criteria for fresh and marine water quality recreational uses Updated water contact use categories Notes on the Action 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 the EPA’s 304(a) recommendations. Refer to the Action Letter and Technical Support Document for Details EPA Action Letter and Technical Support Document dated 04/30/2019 (pdf) (727.76 KB)
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 the Action Letter for Details EPA Action: Partial Approval and Partial Disapproval of Ecology submission (pdf) (4.07 MB, November 15, 2016) Notes on the Action For the criteria that the EPA disapproved, concurrent with this action on Washington’s submittal, the 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. Other Related Information Please refer to the action letter for provisions on which the EPA has not yet taken action.
08/10/2011	Approved WQS • Minor editorial changes and non-substantive revisions. Refer to the 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 the Action Letter for Details • EPA Action letter dated 05/14/08 (pdf) (180.68 KB) Notes on the Action This action supersedes the February 11, 2008 decision in which the 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 the 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 the 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 the 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
12/18/2015	Approved WQS • Various revisions in Parts I-IV of the SMS Refer to the 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 the 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) Notes on the Action Decision was re-approved on April 22, 2011 due to litigation.

Date of EPA Action

Summary of EPA Action

12/18/2015

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

Refer to the 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 the 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)

Notes on the Action

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

Federally Proposed or Promulgated Standards

On November 14, 2022, EPA signed a rule to restore the protective and science-based federal human health criteria (HHC) for the state of Washington’s waters that the EPA had originally promulgated in 2016 but later removed in 2020.
- Federal Human Health Criteria for Washington State Waters
Reconsideration of the EPA’s Partial Approval/Partial Disapproval of Washington’s Human Health Water Quality Criteria – the 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 - the 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 the EPA’s final rule, the 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 the 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