Rulemaking initiated to revise the cold water aquatic life criteria for ammonia and to remove the site specific criteria for the Spokane River.
Status of Rulemaking
Negotiated rulemaking meeting October 6, 2026. Rule Draft 2 comment deadline October 13, 2026.
Overview
This rulemaking proposes to update cold water aquatic life ammonia criteria using a recalculation of EPA’s 2013 recommendations which substitutes eastern unionid species toxicity values with recently developed western unionid (Idaho resident) toxicity values. The new criteria are to be temperature and pH dependent and to contain an acute (1-hour maximum) and chronic (30-day average maximum) component.
DEQ also proposes removing the site-specific ammonia criteria for the Spokane River, which are currently identical to the statewide criteria. The species and conditions in this waterbody do not warrant a separate criteria from the proposed new statewide criteria.
Meeting Details
Method for Participating and Submitting Comments
Those interested in participating in the negotiated rulemaking process are encouraged to attend the scheduled meeting.
For those who cannot participate by attending the meeting, public comment opportunities will be made available throughout the rulemaking process.
Submit all written comments and direct questions to:
Beth Spelsberg
Department of Environmental Quality
1410 N. Hilton, Boise, ID 83706
Elizabeth.Spelsberg@deq.idaho.gov
Proposed Rule
Information pending.
Negotiated Rule Documents and Meeting Presentations
| Negotiated Rule Documents and Meeting Presentations | Date of Meeting | Written Comment Deadline |
|---|---|---|
| Negotiated Rule Draft 2 | 10/06/2026 | 10/13/2026 |
| Ammonia Recalculation Correction | 08/12/2026 | NA |
| Meeting 1 Presentation – includes corrected equation on p. 25 and 26 and corrected acute criteria table on p. 29 | Corrected 08/12/2026 | NA |
| Negotiated Rule Draft 1 | 08/10/2026 | 08/17/2026 |
Public Comment
Legislative Rule Review
Information pending.
Meeting of the Idaho Board of Environmental Quality
Information pending.
Rulemaking Documents Required by Idaho Administrative Procedures Act
Additional Information
Information pending.