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Idaho NPDES Program Authorization


The Idaho Department of Environmental Quality (IDEQ) is seeking approval to administer the Idaho Pollutant Discharge Elimination System (IPDES) program regulating discharges of pollutants into waters of the United States under its jurisdiction.

If EPA approves the IPDES program, the IDEQ will administer this program in place of the National Pollutant Discharge Elimination System (NPDES) program currently administered by the EPA. If approved, NPDES program authority will transfer from EPA to IDEQ on or after July 1, 2018.

EPA will retain authority for NPDES permits for discharges to tribal waters.

Public Comment Period

EPA accepted public comments and testimony on Idaho's IPDES application from August 11 through October 10, 2017. Copies of all public comments received, and a transcript from the public hearings, are available below. EPA is in the process of responding to comments.

Public Hearings and Informational Meetings

EPA and the Idaho Dept. of Environmental Quality held a series of public meetings at the locations listed below. Presentations and handouts from the public meetings are available.

  • September 11, 2017 at Central Public Library in Idaho Falls.
  • September 12, 2017 at Twin Falls Public Library.
  • September 13, 2017 at Boise Public Library.
  • September 14, 2017 at Lewiston Community Center.
  • September 15, 2017 at Coeur d'Alene Public Library.

Related Information


Application Documents

Idaho submitted the following documents to EPA on August 31, 2016 (and updated on August 1, 2017) as part of its program submission.

The following links exit the site Exit
  1. Letter from Idaho governor to EPA requesting approval of State's application (PDF)(2 pp, 488 K, About PDF) - August 9, 2016
  2. IPDES Program Description (PDF)(443 pp, 26 MB) - Revised July 2017. Document describes how the state will issue IPDES permits, ensure compliance with permit conditions, conduct enforcement, as well as fund and manage the program including programmatic information and data.
  3. Statement from Idaho Attorney General's Office (PDF)(92 pp, 1 MB) - August 1, 2017. Letter and supporting information confirming that the state’s laws and regulations provide sufficient authority to the state to implement the discharge, pretreatment, and biosolids components of the NPDES program.
  4. Memorandum of Agreement (MOA) Between Idaho and EPA Region 10 (PDF)(83 pp, 1 MB) - Document establishes, in part, timeframes for a phased approach for the state to assume authority.
    • Note: On August 29, 2017, EPA provided a correction to Appendix F of the MOA (see "Additional Correspondence" below).
  5. Water Quality Planning in Idaho: Continuing Planning Process (PDF)(4 pp, 261 K)
  6. Applicable State statutes and regulations:

To review supplemental documents, visit Idaho Pollutant Discharge Elimination System Program Application.Exit

Additional Correspondence

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