Overview
Preemption classification
Tier C — Dual preemption
Pro-housing: SB 323 (middle housing), SB 528 (ADUs), SB 243 (commercial-to-residential), 2025 parking and single-stair reform. Restricts locals: rent control preemption (2023), bans mandatory inclusionary zoning (2021). Most dual-aggressive red state in the country.
Governance
Statewide
Building and zoning code adoption is mandated at the state level.
Adopted building codes
Local option to enforce
City-level IBC adoptions (2)
| City | IBC | Amendment notes |
|---|---|---|
| Billings | 2021 | |
| Helena | 2021 |
View building-code adoption for Montana →
4 of 5 codes adopted (IBC, IRC, IECC, NEC)
Profiled counties
Cities
Showing 3 of 3
| City | Population | Code | Status | Issues |
|---|---|---|---|---|
| Billings | — | Billings Municipal Code, Title 27 — Unified Development Code (Land Use and Zoning) · 13 districts | V2 ✓ | freshness:volatiledata:gaps-present |
| Helena | — | Helena City Code, Title 11 — Zoning and Development · 9 districts | V2 ✓ | freshness:volatiledata:gaps-present |
| Townsend | — | City of Townsend Municipal Code (town code) + Broadwater County zoning regulations (for ETJ / unincorporated land around Townsend) · 4 districts | V2 ✓ | data:gaps-present |
Research status
Data quality
100%completeness3 confirmed