Montana SB 323 — Duplex By-Right in Cities >=5,000 (MT)
Tracked preemption from the Montana overlay bundle.
Overview
← All state preemptionsMontana overlay roll-upMontana zoning wikiMontana building codesFederal overlaysGlossaryFederal-conflict: Yes
Effective
2023-10-01
Sunset
—
Authority
state
Scope
state:MT
Other Montana preemptions
Montana SB 528 — ADU Statewide By-RightMontana SB 382 — Montana Land Use Planning ActMontana HB 819 — Minimum Lot Size Cap in Cities >=5,000Montana HB 337 — Parking Minimum Cap for Multifamily Near TransitMontana SB 245 — Density Restriction Preemption in Residential ZonesMontana Property Tax Mill Levy Cap
Trigger predicate
When this evaluates true for a parcel, the law's preempted fields take precedence over base zoning.
AND
city.population≥5000parcel.base_zone_category==res_sf
Preempted fields
3 fields on the base district schema are rewritten when the trigger fires.
| Field | Op | Value | Note |
|---|---|---|---|
base_districts[category=res_sf].allowed_uses | add | duplex | |
base_districts[category=res_sf].max_units_per_lot | floor_at | 2 | |
review_type | waive_discretionary | — |
Citation
Authority source
Montana SB 323 (2023) — codified at MCA Title 76, Chapter 2
§ SB 323 §1–3
Research notes
Requires cities with population >=5,000 to allow duplexes by-right on any lot zoned for single-family residential use. Part of the 2023 Montana Miracle housing package.