Administrative Rules of Montana Department 17 - ENVIRONMENTAL QUALITY
Here’s a structured overview of Department 17 – Environmental Quality in the Administrative Rules of Montana (ARM):
🏛️ Title Overview: Department 17 – Environmental Quality
Major chapters include:
Chapter 17.4 – Procedural Rules
Covers rulemaking procedures, penalty calculations, electronic filing, and procedures under the Montana Environmental Policy Act (MEPA) (regulations.justia.com).
Includes Subchapter 17.4.6 (MEPA rules like EA/EIS thresholds—see ARM 17.4.607) (regulations.justia.com).
Chapter 17.8 – Air Quality
Sets standards for ambient air, emissions, permitting, open burning, and major stationary sources (regulations.justia.com).
Chapter 17.20 – Major Facility Siting
Governs the permitting of large-scale facilities and required applications to DEQ and Environmental Review Board (regulations.justia.com).
Chapters 17.30 & 17.36 – Water Quality & Subdivisions
Chapter 17.36 covers public water systems, subdivision sanitation, nondegradation rules (e.g., mixing zones) (prod-deq.mt.gov).
Other DEQ program-specific chapters
Include underground storage tanks (17.56), solid waste, waste water, floodplain regs, etc.—detailed under DEQ’s “Laws and Regulations” listing (deq.mt.gov, deq.mt.gov).
🔧 Selected Key Rules & Recent Updates
MEPA Process – ARM 17.4.607
Defines criteria for Environmental Assessments (EA) and Environmental Impact Statements (EIS), including exemptions and thresholds (regulations.justia.com).
Air Quality – Chapter 17.8
Comprehensive rules on permits, emissions, open burning, compliance assurance, and federal SIP-approved regulations (regulations.justia.com).
Major Facility Applications – ARM 17.20.801
Requires developers to provide sufficient detail for environmental standards compliance across primary and alternate facility sites (regulations.justia.com).
Water Quality & Nondegradation – Chapter 17.36
July 5, 2024 amendments to mixing zone rules and septic criteria under Senate Bills 285 and 327 (deq.mt.gov).
Aug 23, 2024 repeal of predetermination letter requirement in subdivision sanitation rules (prod-deq.mt.gov).
Sept 20, 2024 adoption of Circular DEQ‑8 for storm‑water drainage in subdivisions (deq.mt.gov).
🗓️ Recent Rulemaking Actions (last 24 months)
DEQ’s “Laws and Regulations” portal summarizes recent rule activity (deq.mt.gov):
| Date | Rulemaking Activity |
|---|---|
| Mar 2025 | MAR 17‑451 – air, water, and storage tanks amendments |
| Jan 11, 2025 | MAR 17‑449 – procedural rule amendments in Chapter 17.4 |
| Sep 21, 2024 | MAR 17‑446 & 17‑444 – Underground Storage Tank and Subdivision rules |
| Aug 24, 2024 | MAR 17‑447 & 17‑445 – Water and Air Quality amendments |
| Jul 27, 2024 | MAR 17‑443 – Major facility siting updates |
| Jul 5, 2024 | MAR 17‑439 – Nondegradation rule updates (deq.mt.gov, deq.mt.gov, prod-deq.mt.gov, prod-deq.mt.gov) |
✅ Next Steps for You
Need full rule text? I can fetch specific ARM sections (e.g., 17.36.103(a) or 17.8.301).
Interested in tracking public comment or upcoming DEQ hearings? The DEQ site lists archived and current notices (deq.mt.gov).
Curious about a particular program area? (e.g., air permits, septic systems, EIS process)
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