Protecting Public Health and the Environment.

Water Quality: Docket No. 58-0102-1301 - Final Rule

Rulemaking initiated in response to EPA disapproval of the water quality standards provision that exempts, from Tier II antidegradation review, those activities or discharges determined to be insignificant (de minimus exemption).

Public Comment Opportunities / Negotiated Rulemaking History

Rule Package Approved by EPA

Rule Package Submitted to EPA for Approval

Status of Rulemaking

Final rule effective April 11, 2015. Rule package approved by EPA September 26, 2014.

Temporary Rule Justification

Pursuant to Section 67-5226(1)(c), Idaho Code, the governor has found that temporary adoption of the rule is appropriate in order to comply with deadlines in federal programs and, therefore, avoid federal promulgation of Idaho’s water quality standards.

Effective Date

April 11, 2015


DEQ is initiating this rulemaking docket in response to U.S. Environmental Protection Agency (EPA) disapproval of the water quality standards provision that exempts, from Tier II antidegradation review, those activities or discharges determined to be insignificant (de minimus exemption). This provision is set out in IDAPA

DEQ is also proposing to revise IDAPA, which addresses the treatment of water bodies that do not support designated beneficial uses. This section needs to be updated to ensure it is consistent with changes in the Idaho Code and other sections of the water quality standards that have been adopted since the adoption of Section 055. For example, Subsection 055.04, which was adopted in 1997, contains antidegradation provisions which have since been superseded by the antidegradation policy and implementation provisions contained in Idaho Code §39-3603 and IDAPA and 052, which were adopted by the Idaho Board of Environmental Quality (Board) in 2010 and approved by the Idaho Legislature in 2011 (Docket No. 58-0102-1001). 

In November 2010, antidegradation implementation procedures were adopted by the Board and then submitted to the 2011 Idaho Legislature for review (Docket No. 58-0102-1001). Under House Concurrent Resolution 16 (HCR16), the Idaho Legislature rejected certain portions of the rule and approved the remainder of the rule. The 2011 Idaho Legislature also adopted House Bill 153 (HB153) which revised the Idaho Code to include sections addressing the definition of degradation, the treatment of general permits, the identification of Tier II waters, and insignificant discharges or activities (codified at Idaho Code §§39-3601, 39-3602, 39-3603, and 39-3623). The new sections added to Idaho law by HB153 correspond to the portions of the rule rejected by HCR16.

In April 2011, DEQ submitted revisions to its water quality standards administrative rule (Docket No. 58-0102-1001) and corresponding revisions to the Idaho Code to EPA for review and action. In August 2011, EPA approved the revisions as submitted. 

In November 2011, the Board adopted Docket No. 58-0102-1103, which included revisions to make the language on implementation of antidegradation procedures in Idaho’s water quality standards complete and consistent with changes in state law brought about by the 2011 Legislature’s passage of HB153. 

On February 14, 2012, Greater Yellowstone Coalition (GYC) brought an action in the U.S. District Court for the District of Idaho (Court) challenging EPA’s approval of Idaho’s definition of “degradation” of water quality and Idaho’s mandatory exemption from review for de minimus levels of discharge. The de minimus exemption provided for an automatic exemption from Tier II antidegradation review if the added pollution from a new or increased activity would cause less than a 10% cumulative loss of a water body’s assimilative capacity as of July 1, 2011. GYC argued that the de minimus exemption allows too much pollution. On April 24, 2013, the Court granted EPA’s motion for remand of the de minimus issue and gave EPA 90 days to either 1) take a new action on the de minimus provision; or 2) inform the Court that it has determined not to take a new action, and to file a cross-motion for summary judgment and brief in support of that motion regarding the de minimus provision. The Court will retain jurisdiction to ensure a timely remand process and to allow the parties to challenge any new EPA decision in this case.

On July 23, 2013, EPA disapproved the de minimus exemption (EPA disapproval letter is available here). The Clean Water Act provides that if the state does not adopt changes in its rule to address the disapproval within 90 days, EPA shall promulgate a standard for the state. Pursuant to this section of the Clean Water Act, EPA may be required to promptly prepare a proposed rule for the state of Idaho. Adoption of this rule docket will avoid EPA promulgation. 

After consideration of public comments, the rule has been adopted as initially proposed.

Idaho Code §39-3603(2)(c) has been revised by the 2014 Idaho Legislature (House Bill 392). This legislation is consistent with the language in the proposed rule.

Public Comment Opportunities/Proposed Rule

Submit all written comments by mail, fax or email to:

Paula Wilson, Department of Environmental Quality,
1410 N. Hilton,
Boise, ID  83706
Fax: (208) 373-0481

Comment Period/Proposed Rule

December 4, 2013 through January 3, 2014

Public Hearing/Proposed Rule

No public hearings

Public Comments/Proposed Rule

Submitted By Date Received
Greater Yellowstone Coalition 01/02/14

Negotiated Rulemaking History

The text of the proposed rule has been drafted based on discussions held and concerns raised during negotiations conducted pursuant to Idaho Code § 67-5220 and IDAPA On August 7, 2013, the Notice of Negotiated Rulemaking was published in the Idaho Administrative Bulletin, Vol. 13-8, pages 334 through 335, and a preliminary draft rule was made available for public review.  A meeting was held on August 28, 2013. Several members of the public participated in this negotiated rulemaking process by attending the meeting and by submitting written comments. A record of the negotiated rule drafts, written comments received, documents distributed during the negotiated rulemaking process, and the negotiated rulemaking summary is available below.

All comments received during the negotiated rulemaking process were considered by DEQ when making decisions that resulted in drafting the proposed rule.  The proposed rule is the same as Negotiated Rule Draft No. 4 with the exception of Subsection 055.02.a.  Upon review, DEQ revised Subsection 055.02.a. for grammatical purposes. DEQ is now seeking public comment on the proposed rule. 

Negotiated Rulemaking Meeting Schedule

No additional meetings scheduled.

Draft Negotiated Rule

The draft negotiated rule can be obtained here or by contacting Paula Wilson at, (208) 373-0418. 

Draft Negotiated Rule Date Posted Written Comment Deadline
Preliminary Draft (Draft No. 1) 08/08/13 09/06/13
Draft No. 2 08/29/13 09/13/13
Draft No. 3 09/27/13 10/11/13
Draft No. 4 10/28/13 The comment period for this negotiated rulemaking has concluded. The comment period on the proposed rule will commence upon publication of the proposed rule in the Idaho Administrative Bulletin. DEQ intends to publish the proposed rule on December 4, 2013.

Written Public Comments/Negotiated Rulemaking

Comments Date Received Submitted By
Comment on Draft No. 2 09/13/13 Greater Yellowstone Coalition
Comment on Draft No. 2 09/13/13 Idaho Association of Commerce & Industry
Comment on Draft No. 3 10/11/13 Greater Yellowstone Coalition
Comment on Draft No. 3 10/11/13 Idaho Association of Commerce & Industry

Documents Distributed for Negotiated Rulemaking

Document Date Posted
Negotiated Rulemaking Summary 11/27/13
Rulemaking Schedule 08/02/13
EPA Disapproval Letter and Technical Support Document (7/23/13) 08/02/13


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Staff Contacts

Water Quality Standards Lead
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0502

Administrative Rules Coordinator
Paula Wilson
DEQ State Office
Attorney General's Office
1410 N. Hilton
Boise, ID 83706
(208) 373-0418

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