Does Montana Require CO Detectors? Rental Duties and Local Codes

Last verified: February 18, 2026

Montana carbon monoxide detector laws combine a clear rental statute with statewide building-code adoption. MCA 70-24-303(1)(g) requires landlords to install an approved detector in each rental dwelling unit under their control and verify operability at the start of tenancy, and the statute assigns tenants an ongoing duty to keep the device in working order.

Montana also adopts statewide IRC and IBC code editions, so new residential and hotel occupancies with fuel-burning appliance or attached-garage trigger conditions are covered through code enforcement pathways. Montana rulemaking materials reference placement near sleeping areas and UL 2034 alignment for compliant CO detection.

Operators should keep move-in verification records, maintenance logs, permit files, and written notice timelines to support both code compliance and civil enforcement processes.

Quick Safety Summary

CO detector requirements for Montana
Applies to homes?	Yes
Applies to rentals?	Yes
Applies to hotels/STRs?	Yes

When Are CO Alarms Required?

Buildings with fuel-burning appliances
Buildings with attached garages
New construction
When building permits are required
Rental dwelling units under landlord control are explicitly covered by MCA 70-24-303(1)(g).

Where to Install CO Alarms

Rulemaking adoption materials describe placement outside each separate sleeping area in the immediate vicinity of bedrooms.

For detailed placement guidance beyond legal requirements, see where to place carbon monoxide detectors.

Device Requirements

Approved detectors must meet statutory approval language tied to recognized testing and labeling pathways.
Rulemaking responses reference UL 2034 compliance and allow combination units when CO components meet required standards.

Landlord and Tenant Responsibilities

Landlord: Landlords must install approved detectors in each covered rental dwelling unit and verify operability at tenancy start.

Tenant: Tenants must keep required detectors in good working order during occupancy.

Lease documents should define testing, battery replacement, and damage-reporting expectations.

Enforcement

Enforced by: Civil landlord-tenant remedy framework under Title 70, Chapter 24, Part 4.

Enforcement typically occurs:

When a landlord fails to cure written notice regarding required detector conditions within statutory timelines.
During tenancy disputes involving habitability duties tied to detector obligations.

Administrative rule language states these provisions are enforced through civil remedies rather than criminal penalty schedules.

Penalties for Non-Compliance

The cited Montana sections do not provide a stand-alone criminal fine table for CO detector violations and instead rely on civil landlord-tenant remedies.

MCA 70-24-303 with related remedy pathways in MCA 70-24-406 and 70-24-407.

Additional Notes

This file treats statewide obligations as clearly confirmed for rentals and for new-construction homes and hotels through statewide code adoption.
Operators should preserve civil-remedy documentation, including written notices and cure timelines.

Official Sources & References

Montana Code Annotated 70-24-303 landlord duty to maintain premises — 70-24-303(1)(g) (state code, accessed 2026-02-17)
Primary statewide rental-duty text for installation, move-in operability, and tenant maintenance expectations.
Montana Code Annotated 70-20-113 approved detector definition context — 70-20-113 (state code, accessed 2026-02-17)
Definition support for approved detector language referenced by the rental statute.
Montana Administrative Register notice of adoption for NEW RULE I 24.320.301 — Adoption responses on placement and UL 2034 alignment (building code, accessed 2026-02-17)
Rulemaking record used for placement and listing interpretation context.
Montana Department of Labor and Industry — Current Adopted Building Codes — Statewide adoption of current IBC and IRC editions (building code, accessed 2026-02-18)
Official statewide code adoption list supporting new-home and hotel applicability through code pathways.

Disclaimer: This information is provided for general guidance and is not legal advice. Requirements may vary by city, county, and building type. Always verify current rules with local authorities and official sources.

Frequently Asked Questions

Which Montana statute creates the main landlord CO detector duties?

MCA 70-24-303(1)(g) is the core statewide statute for Montana rental compliance. It requires landlords to install approved carbon monoxide detectors in each rental dwelling unit under their control and verify that devices work at the start of tenancy. The same section also assigns ongoing maintenance responsibility during occupancy. Teams should cite this section directly in lease exhibits and turnover checklists instead of relying on generic safety language. That section-level approach makes disputes easier to resolve.

Which properties are clearly covered statewide in Montana?

Rental dwelling units are clearly covered by MCA 70-24-303(1)(g), and statewide adopted IRC/IBC pathways cover new homes and hotels when trigger conditions are present. The rental statute and building-code pathways work together, so teams should classify each property by occupancy and project status before applying one default rule. Montana records should include a written scope determination that names the governing section, code edition, and decision-maker for each asset. This prevents classification errors during audits and inspections.

Where should detectors be placed and what listing standard is referenced?

Montana rulemaking adoption text references placement outside separate sleeping areas in the immediate vicinity of bedrooms and describes UL 2034 alignment for CO detection performance. Operators should treat these references as implementation guidance alongside statutory approval requirements in the rental law. Installation files should document exact placement, model number, and commissioning date for each unit. That detail supports maintenance planning and lowers disagreement risk during inspections or tenant claims in Montana portfolios.

What happens if a landlord ignores CO detector repairs in Montana?

The cited framework points to civil landlord-tenant remedies rather than a dedicated statewide criminal fine schedule for detector violations. When required corrections are not completed after valid notice, disputes can escalate through remedy pathways that affect tenancy and damages. Operators should therefore treat notice response times as critical compliance controls. Maintain a single timeline showing notice receipt, repair completion, and verification so legal and property teams can prove that corrective duties were handled promptly. In Montana, cite MCA 70-24-303 and related remedy sections in every escalation file.

Do all-electric Montana homes fall outside statewide requirements?

Not always, and the answer depends on occupancy type and governing code path. The most explicit statewide statutory duty in this file is for rentals, while broader home scenarios can involve local adoption decisions and project-specific interpretations. Owners should avoid blanket assumptions based only on utility profile and document the exact rule basis for each determination. Reassess that determination if the property use, layout, or adopted local code edition changes. Montana teams should capture that review in annual compliance audits.

How does Montana compare with Wyoming for Mountain-region policy planning?

Montana in this file is anchored in landlord-tenant rental duties with civil remedy enforcement, while Wyoming statewide text is clearest in child care rules plus adoption-by-reference code pathways. Regional operators should not deploy one common Mountain-state template without occupancy-level branching. For side-by-side planning, review Wyoming CO detector laws and compare scope triggers, enforcement channels, and documentation controls. Montana program owners should assign separate review checkpoints for both states before policy release.

Practical CO Detector Guides

Beyond legal requirements, these guides help you choose, install, and maintain CO alarms:

Where to place carbon monoxide detectors — room-by-room placement recommendations
CO detector beeping patterns — what different alarms mean
What to do if your detector goes off — emergency response checklist
CO resources and links — official agencies and safety information