EPA Actions on Proposed Standards

Water quality standards adopted and submitted to EPA after May 30, 2000, are not effective for Clean Water Act (CWA) purposes until EPA approves them (40 CFR 131.21). This is known as the Alaska Rule.

Several sections of Idaho’s Water Quality Standards (IDAPA 58.01.02) are under EPA review, and until these are acted upon, their use in CWA programs, such as Idaho Pollutant Discharge Elimination System (IPDES) permits or total maximum daily loads (TMDLs), will not be approved by EPA.

More information on dockets pending EPA approval is available on the DEQ Rulemakings web page.

Subject Matter Docket Number	Effective Date of State Rule	Date of Submittal to EPA	Summary	Affected Sections	Effective for CWA Purposes	Status of EPA Review
Recreation Criteria for Bacteria 58-0102-2001	07/01/21T Docket No. 58-0102-2001 pending rule revisions included in Omnibus Docket No. 58-0000-2100 and adopted as a temporary rule with an effective date of 07/01/21.	12/01/21 (DEQ submittal letter)	Revision of recreation criteria for bacteria and clean up Section 260, Variances from Water Quality Standards	251 260	The current Idaho Administrative Code applies.	Approved on 2/1/22 (EPA approval letter and technical support document)
De minimis Heat Additions 58-0102-1803	04/11/19	04/15/19 (DEQ submittal letter)	This revision allows de minimis additions of heat in waters that exceed applicable temperature criteria.	401.01	This rule docket was promulgated so that the existing rule, which continues to be effective for CWA purposes, remains in the current Idaho Administrative Code until EPA approves the rule revisions.	EPA Action Letter and Technical Support Document (12/19/24) EPA disapproved Docket 58-0102-1803 with the exception of the approval of non-substantive revision in 401.01.c(e): addition of “above the natural background conditions.”
Aquatic Life Criteria for Three Toxics & Description of Recreational Use 58-0102-1802	04/11/19	01/20/22 (DEQ Submittal Letter)	Adopt aquatic life criteria for acrolein, carbaryl, and diazinon, and clarify description of recreational use.	210.01 100.02	This rule docket was promulgated so that the existing rule, which continues to be effective for CWA purposes, remains in the current Idaho Administrative Code until EPA approves the rule revisions.	Pending
Domestic Water Supply as a Beneficial Use 58-0102-1703	04/11/19	07/19/19 (DEQ Submittal Letter)	Designated domestic water supply as a beneficial use in water bodies where the Safe Drinking Water Information System indicates an active surface water intake or ground water under direct influence of surface water and where domestic water supply is not currently designated.	100.03 110 120 140 160 252	The current Idaho Administrative Code applies.	Approved on 09/16/19 (EPA approval letter)
Update Selenium Criteria for Aquatic Life 58-0102-1701 58-0102-1901 (287.03 revised to line up with EPA’s 7/9/19 action letter)	03/28/18	08/24/18 (DEQ submittal letter)	Updated selenium criteria for aquatic life. Document Referenced in Rule: >Aquatic Life Ambient Water Quality Criterion for Selenium – Freshwater, EPA-822-R-16-006,Appendix K: Translation of a Selenium Fish Tissue Criterion Element to a Site-Specific Water Column Value (June 2016)	210.01 287	The current Idaho Administrative Code applies, except for application of 287.03 to certain water bodies. Under 58-0102-1901, 287.03 was revised to line up with EPA’s 7/9/19 action letter. Until EPA approves the application of any new site-specific selenium criterion to North Fork Sage and Pole Canyon Creeks, and their tributaries, the criterion at 287.05 is the effective selenium criterion for CWA purposes in North Fork Sage Creek, Pole Canyon Creek, and their tributaries.	Approved on 7/9/19 except for application of 287.03 to certain water bodies. (EPA action letter)
Update Copper Criteria for Aquatic Life 58-0102-1502	03/28/18	01/08/19 (DEQ submittal letter)	Updated copper criteria for aquatic life. Documents Referenced in Rule: “US EPA WQC Calculation” for copper in Biotic Ligand Model (BLM) Version 3.1.2.37 (October 2015) BLM Version 3.1.2.37 is the current recommended criterion as of October 2015. “Aquatic Life Ambient Freshwater Quality Criteria – Copper:“ EPA-822-R-07-001 (February 2007) Implementation Guidance for the Idaho Copper Criteria for Aquatic Life: Using the Biotic Ligand Model, Idaho DEQ (November 2017) >Statewide Monitoring for Inputs to the Copper Biotic Ligand Model, Idaho DEQ (August 2017) (referenced in Implementation Guidance)	210.01 210.02 210.03	The current Idaho Administrative Code applies.	Approved on 05/02/19 (EPA approval letter)
Designation and Revision of Beneficial Uses (Use Attainability Analysis) 58-0102-1501	03/25/16	12/30/16 (DEQ submittal letter)	Added language that is consistent with the federal regulations for designating and revising uses assigned to waterbodies, providing basis for guidance on the use designation/revision process.	010 (definition added in docket 58-0102-1501: Use Attainability) 102	The current Idaho Administrative Code applies.	Approved on 08/23/18 (EPA approval letter)
Mixing Zone Policy 58-0102-1401	04/11/15	10/26/16 (DEQ submittal letter)	Updated DEQ’s Mixing Zone Policy to take into account modern tools for evaluating mixing, lessons learned from years of implementation, and to provide greater clarity for DEQ and the regulated community. Mixing Zone Rule Crosswalk	010 (definitions updated in docket 58-0102-1401: Bioaccumulative Pollutants, Thermal Shock, and Zone of Initial Dilution) 060	The current Idaho Administrative Code applies.	Approved on 12/16/19 EPA Approval Letter
Antidegradation Implementation Procedures 58-0102-1001 58-0102-1103 58-0102-1301	03/18/11 03/09/12 06/14/14T 04/11/15	04/15/11 06/8/12 07/8/14	Adoption of methods for implementation of antidegradation policy 58-0102-1001 >2011: Pending rule reviewed by legislature. Certain sections rejected (HCR16) and revised (HB153) >April 15, 2011: DEQ submitted Docket No. 58-0102-1001 to EPA (DEQ submittal letter) >August 18, 2011: EPA approved Docket No 58-0102-1001. (EPA approval letter and support document) >February 2012: Greater Yellowstone Coalition (GYC) challenged EPA’s approval. >July 23, 2013: EPA rescinded approval of the de minimis exemption (EPA disapproval letter and TSD) 58-0102-1103 >July 2011: DEQ initiated rulemaking to make revisions consistent with 2011 legislative action. >June 8, 2012: DEQ submitted Docket No. 58-0102-1103 to EPA (DEQ submittal letter) 58-0102-1301 >August 2013: DEQ initiated negotiated rulemaking. >July 8, 2014: DEQ submitted revised de minimis exemption to EPA (DEQ submittal letter and supplemental justification) >September 26, 2014: EPA approved Idaho’s revised de minimis exemption (EPA approval letter)		The current Idaho Administrative Code applies.	58-0102-1301 58-0102-1103 approved on 09/26/14 (EPA approval letter)
Update Idaho’s Human Health Criteria 58-0102-0503 58-0102-1201	04/11/06 03/25/16	07/07/06 12/13/16 (DEQ submittal letter)	58-0102-0503 Updated 167 human health criteria for 88 compounds. 58-0102-1201 Updated human health criteria for 104 toxic substances (10 of which are new), plus an additional fish-plus-water criterion for copper based on the drinking water maximum contaminant level (MCL). There are 208 revised or new criteria, consisting of 94 revised and 10 new criteria based on exposure to toxic substances from the consumption of fish and ingestion of water plus an additional fish-plus-water criterion for copper, and 94 revised and 10 new criteria based on exposure to toxic substances from the consumption of fish alone. In addition, although new input values were used, the values for the antimony fish only criterion and the bromoform fish-plus-water criterion did not change; these are counted as revised criteria. With this revision, Idaho will have updated all of its human health criteria except those for arsenic, methylmercury, and asbestos. Document Referenced in Rule: >Idaho Human Health Criteria Technical Support Document (December 2015)	010 (definition revised in docket 58-0102-1201: Harmonic Mean) 070.08 210.01 210.03 210.04 210.05 400.06	The current Idaho Administrative Code applies.	Approved on 04/04/19 (EPA approval letter) 58-0102-0503 Disapproved on 05/10/12 (EPA disapproval letter) On 08/06/12, DEQ notified EPA of its intention to initiate a negotiated rulemaking to revise the human health criteria for toxic pollutants (DEQ response letter).
Hells Canyon Site-Specific Salmonid Spawning Criterion for Temperature 58-0102-1102	03/29/12	06/08/12 (DEQ submittal letter)	Modified the existing site-specific temperature criterion to protect fall Chinook spawning below Hell’s Canyon Dam by providing for a two week transition in temperatures from October 23 through November 6.	286	The current Idaho Administrative Code applies.	Approved on 11/21/19 (EPA approval letter)
Thermal Treatment Requirements 58-0102-1101	06/30/11 (temporary rule) 03/29/12 (final rule)	07/20/11 (DEQ submittal letter) 08/07/12 (DEQ submittal letter)	Removed the numeric limits on point source induced changes in receiving water temperature.	278.05 278.06 278.07 401.01	For Section 278, the current Idaho Administrative Code applies. The previous treatment requirements in section 401.01 published in 2011 Idaho Administrative Code continue to apply.	278.05 278.06 278.07 Approved on 10/27/11 (EPA action letter) EPA Action Letter and Technical Support Document (12/19/24) Disapproval of revisions in 401.01
Mercury/Aquatic Life 58-0102-0302	04/06/05	08/08/05 (DEQ submittal letter)	In 2005, Idaho adopted EPA’s recommended methylmercury fish tissue criterion for protection of human health. The decision was made to remove the old tissue-based aquatic life criteria and rely on the fish tissue criterion to provide protection for aquatic life as well as human health. Thus, published Idaho WQS do not have mercury water column criteria for the protection of aquatic life. While EPA approved Idaho’s adoption of the fish tissue criterion in September 2005, it had withheld judgment on Idaho’s removal of aquatic life criteria. Document Referenced in Rule: Implementation Guidance for the Idaho Mercury Water Quality Criteria	210.01 210.03	The water column criteria for total recoverable mercury published in 2004 Idaho Administrative Code continue to apply.	Disapproved on 12/12/08 (EPA disapproval letter)
Seasonal Cold Water Use and Temperature Criteria 16-0102-9704 Seasonal cold water use and temperature criteria adopted 58-0102-0002 Temperature criteria for seasonal cold water use revised	04/05/00 03/30/01	04/26/00 (DEQ submittal letter) 05/29/03 (DEQ submittal letter)	Idaho first adopted seasonal cold water use and temperature criteria in April 2000. In March 2001, Idaho revised its temperature criteria for the seasonal cold water use.	250.03 100.01.c 140.11 Little Camas Creek Reservoir Unit SW-7	The following sections submitted to EPA after May 30, 2000, are not effective for CWA purposes: 140.11, Little Camas Creek Reservoir, Unit SW-7, designation of seasonal cold water aquatic life use, and 250.03.b. published in the current Idaho Administrative Code. The following sections were submitted before May 30, 2000, and remain in effect for CWA purposes despite EPA’s disapproval: 250.03.b. and c. as published in the 2000 Idaho Administrative Code and 100.01.c. and 250.03.a. published in the current Idaho Administrative Code.	16-0102-9704 58-0102-0002 Disapproved on 06/09/20 (EPA disapproval letter and technical support document)
Bull Trout Temperature Criterion 16-0102-9701 58-0102-0002	03/28/98 03/30/01	05/29/03 (DEQ submittal letter)	Idaho first adopted bull trout temperature criteria in 1998. These criteria were revised in 2001 and submitted to EPA for approval in 2003. On September 7, 2021, EPA approved the new and revised Idaho bull trout spawning and rearing criteria. However, the 1997 federally promulgated temperature criterion of 10ºC for 7-day average maximum daily temperatures from June through September continues to be effective for CWA purposes for waters specified in the federal rule until EPA withdraws the federal rule (40 CFR 131.33). For waters where both the Idaho bull trout spawning and rearing criteria and the 1997 federally promulgated criterion are effective, the more stringent criteria will be the applicable criterion.	250.02.g. 250.02.g.i.	Until EPA withdraws the federal rule, the 1997 federally promulgated temperature criterion of 10ºC for 7-day average maximum daily temperatures from June through September continues to be effective for CWA purposes for waters specified in the federal rule (40 CFR 131.33). For waters where both the Idaho bull trout spawning and rearing criteria and the 1997 federally promulgated criterion are effective, the more stringent criteria will be the applicable criterion.	16-0102-9701 58-0102-0002 Approved on 09/07/21 (EPA approval letter and technical support document)
Arsenic Human Health Criteria 16-0102-9501 6.2 µg/L 0.02 µg/L adopted 16-0102-9801 50 µg/L adopted 58-0102-0801 10 µg/L adopted 58-0102-1801 negotiated rulemaking to update HHC for arsenic 58-0102-2201 revisions negotiated under 58-0102-1801 adopted	03/08/95 12/01/97 (temporary rule) 03/19/99 03/29/10 04/06/23	1995 1999 06/21/10 (DEQ submittal letter) 07/06/23 (DEQ submittal letter and technical justification)	In 2008, Idaho adopted 10 µg/L as its CWA arsenic criterion for both exposure through fish consumption only and exposure through drinking water+fish consumption, choosing the SDWA MCL due to concerns about background levels that exceed EPA’s 304(a) criteria. EPA approved this action in 2010. In June 2015, Northwest Environmental Advocates challenged EPA’s 2010 approval. Court remanded action back to EPA. On 09/15/16 EPA disapproved Idaho’s adoption of 10 µg/L. Neither EPA nor the state of Idaho has promulgated replacement criteria. On 9/29/23 DEQ received the EPA Action Letter and Technical Support Document approving 58-0102-2201 with exception of disapproving the provision, in IDAPA 58.01.02.210.03.e.v.(4), to calculate bioaccumulation factors using “… other scientifically defensible method for deriving protective BAF.”	210.01 210.03 210.05	The current Idaho Administrative Code applies. EPA Action Letter and Technical Support Document received 9/29/23. EPA approved Docket No. 58-0102-2201 with exception of disapproving the provision, in IDAPA 58.01.02.210.03.e.v.(4), to calculate bioaccumulation factors using “… other scientifically defensible method for deriving protective BAF.”	16-0102-9501 Approved on 06/25/96 16-0102-9801 No action taken 58-0102-0801 Approved on 07/07/10 (EPA approval letter) EPA’s 2010 approval of 58-0102-0801 was remanded back to EPA Consent Decree, NWEA v EPA (06/07/16) 58-0102-0801 and 16-0102-9801 Disapproved on 09/15/16 (EPA disapproval letter) 10/31/17 DEQ letter in response to EPA’s disapproval April 2018 DEQ initiated rulemaking 58-0102-1801 Rulemaking deadlines extended Unopposed Motion to Modify Consent Decree, NWEA v EPA (motion granted on 06/15/18) Unopposed Second Motion to Modify Consent Decree, NWEA v DEQ (order granting motion entered on 06/21/22) (extending the Consent Decree ¶ 5 deadlines to 11/15/23 and the ¶ 6 deadlines to 11/15/24) EPA Action Letter and Technical Support Document (9/29/23)
Variance for Page Wastewater Treatment Facility 58-0102-0002	03/30/01	05/29/03 (DEQ submittal letter)	This revision grants a variance to the South Fork Coeur d’Alene River Sewer District (Page Wastewater Treatment Facility) from meeting water quality standards for ammonia, chlorine, cadmium, lead, and zinc discharged to the West Page Swamp.	previous sections 260.02.a. 260.02.b.	In 2010, EPA disapproved the variance. In 2021, Subsections 260.02.a. and b. were deleted (dockets 58-0102-2001 and 58-0000-2100).	Disapproved on 05/07/10 (EPA disapproval letter)