---
type: "Bill"
title: "Revise categorical exclusions from nondegradation authorization"
description: "Revise categorical exclusions from nondegradation authorization"
jurisdiction: "us/states/mt"
legislature: "Montana Legislature"
session: "2025"
identifier: "HB 923"
citation: "Montana HB 923 (2025)"
classification: ["bill"]
subjects: ["Appropriations", "Environmental Protection", "Rule Making", "Water"]
status: "enacted"
primary_sponsors: ["Llew Jones"]
version_count: 34
action_count: 37
vote_count: 6
first_action: "2024-11-11T22:22:16+00:00"
last_action: "2025-05-19T13:45:04+00:00"
source: "openstates"
source_identifier: "ocd-bill/98836bf8-5f00-409c-97a6-1916356c6de8"
source_url: "https://bills.legmt.gov/#/laws/bill/2/LC1155?open_tab=sum"
source_hash: "b47cb9ca10505d864e81d28d7343cbcdbce6136e8110ddfa815d585e0a702a7d"
vintage: "2026-07-01"
source_snapshot: "https://data.openstates.org/daily/2026-07-01/public.pgdump"
retrieved_at: "2026-07-06"
confidence: "reported"
tags: ["legislation", "bill", "us-mt"]
---

# Montana HB 923 (2025) — Revise categorical exclusions from nondegradation authorization

## Version chain

The bill's text revisions, in order — the diff chain from filing to enrollment.

1. **HB0923.001.001_Amendments-in-Context_final-full.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=301414)
2. **HB0923_1(1).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=300885)
3. **HB0923_1(2).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303754)
4. **HB0923_1(3).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303755)
5. **HB0923_1(4).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303756)
6. **HB0923_1(5).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303757)
7. **HB0923_1.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=300754)
8. **HB0923_2(1).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303759)
9. **HB0923_2(10).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=314174)
10. **HB0923_2(2).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303760)
11. **HB0923_2(3).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303761)
12. **HB0923_2(4).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303783)
13. **HB0923_2(5).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303784)
14. **HB0923_2(6).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303785)
15. **HB0923_2(7).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303792)
16. **HB0923_2(8).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=305323)
17. **HB0923_2(9).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=308991)
18. **HB0923_2.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=303758)
19. **HB0923_X(1).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=314176)
20. **HB0923_X(10).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=325332)
21. **HB0923_X(11).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=325333)
22. **HB0923_X(12).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=325334)
23. **HB0923_X(13).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=326095)
24. **HB0923_X(14).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=327475)
25. **HB0923_X(2).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=314177)
26. **HB0923_X(3).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=316353)
27. **HB0923_X(4).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=316354)
28. **HB0923_X(5).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=316376)
29. **HB0923_X(6).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=316377)
30. **HB0923_X(7).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=317362)
31. **HB0923_X(8).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=320827)
32. **HB0923_X(9).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=324320)
33. **HB0923_X.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=314175)
34. **LC1155.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=298782)

## Votes

- Do Concur — **49–1** (pass) · upper
- Do Pass — **98–0** (pass) · lower
- Do Pass — **99–0** (pass) · lower
- Do Concur — **46–0** (pass) · upper
- do_pass_as_amended — **14–0** (pass) · lower
- be_concurred_in — **11–0** (pass) · upper

## Sponsors

- Llew Jones — primary (person)

## Timeline

The legislative action history — every referral, reading, and vote.

- **2024-11-11T22:22:16+00:00** (LC) Drafter Assigned
- **2025-01-05T15:21:43+00:00** (LC) Draft On Hold
- **2025-03-18T21:20:40+00:00** (LC) Draft Taken Off Hold
- **2025-03-23T18:16:56+00:00** (LC) Draft in Legal Review
- **2025-03-23T20:34:26+00:00** (LC) Draft in Edit
- **2025-03-26T15:41:43+00:00** (LC) Draft in Input/Proofing
- **2025-03-28T22:05:40+00:00** (LC) Draft in Final Drafter Review
- **2025-03-28T23:05:06+00:00** (LC) Draft in Assembly
- **2025-03-29T15:04:08+00:00** (LC) Draft Ready for Delivery
- **2025-03-29T15:10:59+00:00** (LC) Draft Delivered to Requester
- **2025-03-29T16:04:13+00:00** (H) Introduced
- **2025-03-29T17:24:28+00:00** (H) Referred to Committee - (H) Natural Resources `referral-committee`
- **2025-03-29T17:57:09+00:00** (H) First Reading `reading-1`
- **2025-03-31T17:44:42+00:00** (H) Hearing - (H) Natural Resources
- **2025-04-01T01:15:56+00:00** (H) Committee Executive Action--Bill Passed as Amended - (H) Natural Resources `committee-passage`
- **2025-04-01T13:50:00+00:00** (H) Committee Report--Bill Passed as Amended - (H) Natural Resources `committee-passage`
- **2025-04-04T17:00:00+00:00** (H) Scheduled for 2nd Reading `reading-2`
- **2025-04-04T20:14:00+00:00** (H) 2nd Reading Passed `reading-2, reading-2`
- **2025-04-05T14:00:00+00:00** (H) Scheduled for 3rd Reading `reading-3`
- **2025-04-05T15:03:00+00:00** (H) 3rd Reading Passed `passage, reading-3`
- **2025-04-05T15:45:51+00:00** (H) Transmitted to Senate
- **2025-04-07T19:13:37+00:00** (S) First Reading `reading-1`
- **2025-04-07T19:30:00+00:00** (S) Referred to Committee - (S) Natural Resources `referral-committee`
- **2025-04-08T15:41:02+00:00** (S) Hearing - (S) Natural Resources
- **2025-04-12T00:05:54+00:00** (S) Committee Executive Action--Bill Concurred - (S) Natural Resources
- **2025-04-12T15:30:00+00:00** (S) Committee Report--Bill Concurred - (S) Natural Resources
- **2025-04-17T19:00:00+00:00** (S) Scheduled for 2nd Reading `reading-2`
- **2025-04-17T23:27:00+00:00** (S) 2nd Reading Concurred `reading-2, reading-2`
- **2025-04-18T15:00:00+00:00** (S) Scheduled for 3rd Reading `reading-3`
- **2025-04-18T22:09:00+00:00** (S) 3rd Reading Concurred `passage, reading-3`
- **2025-04-18T22:09:11+00:00** (H) Sent to Enrolling
- **2025-04-24T16:04:30+00:00** (H) Returned from Enrolling
- **2025-05-02T17:00:20+00:00** (H) Signed by Speaker `passage`
- **2025-05-06T20:00:00+00:00** (S) Signed by President `passage`
- **2025-05-07T15:03:52+00:00** (H) Transmitted to Governor `executive-receipt`
- **2025-05-13T19:42:00+00:00** (H) Signed by Governor `executive-signature`
- **2025-05-19T13:45:04+00:00** Chapter Number Assigned `became-law`

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/98836bf8-5f00-409c-97a6-1916356c6de8`. Confidence: reported (aggregated from official Montana legislature records).