Official Government Website

EPA Actions on Proposed Standards

Water quality standards adopted and submitted to EPA since May 30, 2000, are not effective for Clean Water Act (CWA) purposes until EPA approves them (see 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 NumberEffective Date of State RuleDate of Submittal to EPASummaryAffected SectionsEffective for CWA PurposesStatus of EPA Review

Recreational Use Criteria

58-0102-2001

07/01/21TPendingRevision of recreational use criteria251This 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.
 

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.
401.01This 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

Recreational Use Criteria and Aquatic Life Criteria for Three Toxics

58-0102-1802

04/11/19PendingRevision of recreational use criteria and adoption of aquatic life criteria for acrolein, carbaryl, and diazinon.100
210
251
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.
 

Domestic Water Supply as a Beneficial Use

58-0102-1703

04/11/1907/19/19
(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

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. 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

04/11/1510/26/16
(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

03/29/1206/08/12
(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.
286The 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
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
)

Approval of 401.01 pending

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 current ongoing rulemaking

03/08/95

12/01/97 (temporary rule) 03/19/99

03/29/10

1995

1999

06/21/10

(DEQ
submittal
letter
)

  • 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.
210.0110 µg/L continues to be the CWA effective arsenic
criterion for both exposure through fish
consumption only and exposure through drinking
water+fish consumption

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 deadline extended

Unopposed
Motion to
Modify Consent Decree, NWEA v EPA
(motion
granted on 06/15/18)

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
)

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