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Water Quality Standards Regulations: Washington

Presented below 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. Also, 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.

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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 below 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 see the related action letter.


Action Summary Table on Washington’s Water Quality Standards

Date of EPA Action Summary of EPA Action Notes on the Action Other Related Information
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.

See Action Letter and Technical Support Document for Details

[See EPA Action Letter and Technical Support Document dated 03/05/2020 ]

   
5/10/2019

Approved WQS

  • Certain human health criteria (HHC) [excluding arsenic] that EPA previously disapproved on 11/15/2016, in part.
See Action Letter and Technical Support Document for Details

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

See Action Letter and Technical Support Document for Details

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)
See Action Letter for Details

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.

Table of Human Health Criteria Effective for Clean Water Act Purposes in Washington (PDF)(3 pp, 202 K)

Please see 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.

See Action Letter for Details
[See EPA Action letter dated 8/10/11 ]

   
05/14/2008

Approved WQS
• Provisions addressing turbidity in freshwater and marine water.

See Action Letter for Details
[See EPA Action letter dated 5/14/08 ]

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
See Action Letter for Details
[See EPA Action letter dated 2/11/08 ]
   
05/23/2007

Approved WQS
• Revised marine chronic aquatic life cyanide criterion for waters outside of Puget Sound.

See Action Letter for Details
[See EPA Action letter dated 05/23/07 ]

   
05/2/2007

Approved WQS
• New and revised language regarding Washington’s antidegradation policy

See Action Letter for Details
[See EPA Action letter dated 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

See Action Letter for Details
[See EPA Action letter dated 12/18/15 ]

   
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.

See Action Letter for Details
Decision was re-approved on April 22, 2011 due to litigation.  

Federally Proposed or Promulgated Standards

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