- [See Water Quality Standards ]
(Effective June 9, 2020) State regulation establishing water quality standards for surface waters of the state. Please note that not all parts of this document are effective for Clean Water Act purposes. Refer to cover pages for more information.
Recent actions along with supporting documents are provided below for reference.
- [See The EPA Review and Action on Idaho's Revised Site-Specific Criteria for Temperature for the Hells Canyon Reach of the Snake River, Idaho Rule Docket 58-0102-1102 ]
- Idaho Water Quality Standards (PDF)(193 pp, 3 MB)
- EPA's April 4, 2019 Action on Idaho's Updated Human Health Criteria (PDF)(47 pp, 2 MB, April 4, 2019)
- Approval and Disapproval of Selenium Aquatic Life (PDF)(50 pp, 2 MB)
- Approval of Idaho’s Copper Aquatic Life Criteria based on the Biotic Ligand Model (PDF)(15 pp, 1 MB)
- Implementation Guidance for the Idaho Copper Criteria for Aquatic Life (PDF)(35 pp, 3 MB)
- EPA Review and Action on Idaho's Revised Site-Specific Criteria for Temperature for the Hells Canyon Reach of the Snake River (PDF)(11 pp, 664 K)
- EPA Review and Action on Idaho’s Water Quality Standards, Seasonal Cold Water Criteria (PDF)(22 pp, 8 MB)
- EPA Review and Action on Idaho's New and Revised Water Quality Standards, Mixing Zone Policy (PDF)(35 pp, 1 MB)