Montana CO Detector Requirements for Hotels and Short-Term Rentals

A single cabin let on Airbnb needs the same Montana licence as a two-hundred-room hotel. MCA Title 50 chapter 51 puts every public accommodation under a Department of Public Health and Human Services licence with annual inspection and sets no minimum room count, and section 50-51-103(2) lets the department make fire and life safety rules for licensed facilities. Montana hotel carbon monoxide detector duties sit beside that in ARM 23.12.601, which adopts the 2021 International Fire Code as the state's minimum fire protection code and leaves Section 915 and Section 1103.9 untouched, so a Group R-1 building is covered new or already standing.

Last verified: August 24, 2026

Key Takeaways

The rule most often quoted at Montana lodging reaches a hotel least. MCA 70-24-303(1)(g) and ARM 24.320.301 sit inside the Residential Landlord and Tenant Act, and MCA 70-24-104(4) excludes transient occupancy in a hotel or motel from that Act by name. ARM 24.320.301 then limits its own enforcement to the tenant remedies in Title 70 chapter 24 part 4, which a hotel guest does not have.
Three tests reach a Montana property and they measure different things: the fire code by occupancy group, the DPHHS licence by business type, and the landlord-tenant rule by tenancy. The fire code is the widest of them, needing no licence and no rental agreement, and nothing in it turns on the size of the operation or the year the building opened.
A whole-house short-term rental is not obviously "a hotel or motel" for the purposes of that exclusion, so the landlord-tenant duty may reach a host where it does not reach a motel. The fire code reaches the host either way, which makes it the safer footing to build an operation on.
An all-electric property with no fireplace and no attached private garage has no trigger under any of the three.
Montana forbids a stricter local building code outright. MCA 50-60-301(2)(a) says a county, city or town may not adopt or enforce a building code more stringent than the one the department adopts or state law requires, with a narrow exception for voluntary energy conservation incentives. Most states allow a stricter local rule on findings or with state approval, and Montana does not allow it in the building code at all.
The fire code is a separate instrument, and Helena used it. Section 13-2-7 of the city code amends the 2021 International Fire Code to require detection in new buildings under Sections 915.1.1 through 915.6 and in existing buildings under Section 1103.9, and then adds a requirement that is rare anywhere: carbon monoxide alarm signals must be transmitted automatically as an alarm signal to a supervising station, and must activate the occupant notification system. A detector sounding in an empty building is worth little, and Helena wants the signal to reach somebody who can act on it.
Read that Helena sentence with one caution. The parallel amendment to Section 907.6.6 carries express exceptions, for single- and multiple-station smoke alarms among others, and the carbon monoxide sentence carries none on its face. That reads as deliberate, and it is worth confirming with the fire code official before assuming a plug-in alarm in a house has to be monitored.

Legal Summary

The rule most often quoted at Montana lodging is the one that reaches a hotel least. MCA § 70-24-303(1)(g) and its implementing rule ARM 24.320.301 sit inside the Residential Landlord and Tenant Act, and MCA § 70-24-104(4) excludes "transient occupancy in a hotel or motel" from that Act by name. ARM 24.320.301 closes the loop from the other end: its own text limits enforcement to the tenant remedies in MCA Title 70, chapter 24, part 4. A guest in a Bozeman motel has none of those remedies, so the landlord-tenant rule is not the instrument that answers for them.

Two instruments do. ARM 23.12.601, made by the Department of Justice under MCA § 50-3-102, adopts the International Fire Code, 2021 edition as Montana's minimum fire protection code, amended into the state in March 2023, and it never touches Section 915 or Section 1103.9. That covers a hotel as a Group R occupancy, new and existing alike. Alongside it, MCA Title 50, chapter 51 puts every public accommodation, including bed and breakfasts and short-term rentals, under a DPHHS licence with annual inspection, and § 50-51-103(2) lets DPHHS make fire and life safety rules for licensed facilities.

Where a short-term rental sits depends on what it is. A whole-house Airbnb is not obviously "a hotel or motel" for the purposes of the exclusion, so the landlord-tenant duty may well reach it. The fire code reaches it either way, which is why the fire code is the safer answer to build an operation on.

Who Is Covered

The fire code covers by occupancy group, which is the widest of the three tests and the one that needs no licence and no rental agreement. IFC 2021 § 915.1.1 reaches Group I-1, I-2, I-4 and R occupancies, and a transient hotel or motel is Group R-1. § 1103.9 applies the same conditions to buildings already standing. Four triggers bring a room in: a fuel-burning appliance or fireplace in the room, a fuel-burning forced-air furnace serving it, fuel-burning equipment elsewhere in the building with a communicating opening, or an attached private garage. Nothing turns on the size of the operation or the year it opened.

The DPHHS licence covers by business type, and it is broad: hotels, motels, bed and breakfasts and tourist homes, which the department's own programme page reads as including Airbnb and VRBO listings. There is no minimum room count, so a single-cabin listing needs the same licence as a two-hundred-room property.

The landlord-tenant rule covers by tenancy, and that is where a hotel drops out. MCA § 70-24-104(4) excludes transient occupancy in a hotel or motel from the Act that ARM 24.320.301 enforces. An entirely electric property with no fireplace and no attached private garage has no trigger under any of the three.

Hotels already standing: covered too. The Montana requirement reaches an existing hotel and not only one being built.

Operator Responsibilities

Commercial hotel and motel operators. The binding technical standard is the fire code. ARM 23.12.601 adopts IFC 2021 and leaves Section 915 alone, so detection is required in guest rooms wherever one of the four triggers exists, and § 915.2.2 puts it inside the guest room unless neither the room nor its attached bathroom holds a fuel-burning appliance and no forced-air furnace serves it. An existing hotel is not outside this: § 1103.9 carries the same conditions into buildings already standing, and Montana's single amendment touching that section adds Group E classrooms rather than removing Group R. On top of that sits the DPHHS licence under MCA Title 50, chapter 51, with annual inspection and the fire and life safety rulemaking power at § 50-51-103(2).

Short-term rental hosts. The DPHHS licence applies the same way, and the fire code applies the same way. Whether MCA § 70-24-303(1)(g) also applies depends on whether the listing counts as transient occupancy in a hotel or motel, which § 70-24-104(4) excludes from the Act. Where it does apply, the host installs an approved detector and verifies it is in good working order at the start of each rental agreement, and § 70-24-303(5) shields the landlord from damages for a detector failure where installation and verification were done.

What the landlord-tenant rule does not do. ARM 24.320.301 places the alarm outside each separate sleeping area and says so explicitly, and it limits its own enforcement to the tenant remedies in MCA Title 70, chapter 24, part 4. Read as a hotel standard it gives the wrong placement and a remedy no hotel guest has. It is the rule for a Montana flat, not for a guest room.

Installation and Technical Requirements

Two rules give two different answers, and which one binds depends on whether the room is a guest room or a let flat.

In a hotel or motel guest room, the fire code governs. IFC 2021 § 915.2.2, adopted unamended by ARM 23.12.601, reads "carbon monoxide detection shall be installed in sleeping units". Moving the alarm out to the corridor is the exception, open only where the guest room and its attached bathroom contain no fuel-burning appliance and no forced-air furnace serves them. A room with a gas fireplace takes an alarm in the room.

In a let flat, ARM 24.320.301 governs, and it puts the alarm outside each separate sleeping area in the immediate vicinity of the bedrooms, to UL 2034 and the manufacturer's written instructions, with no hardwiring requirement stated.

Trigger. Fuel-burning appliance or fireplace, fuel-burning forced-air furnace, fuel-burning equipment elsewhere in the building with a communicating opening, or an attached private garage. An open parking garage built to IBC § 406.5, or an enclosed one built to § 406.6, is not a private garage for this purpose. An entirely electric property with no fireplace and no attached private garage has no trigger.

Existing buildings. IFC § 1103.9 reaches them on the same conditions, with two exceptions worth knowing: alarms may be solely battery operated where the code in force at construction required no carbon monoxide detection, and a detection system under § 915.5 is an accepted alternative to alarms.

Verification. Where the landlord-tenant duty applies, MCA § 70-24-303(1)(g) requires the operator to confirm good working order at the start of each rental agreement, which for a nightly booking means before each arrival.

Enforcement

Three enforcers, and the fire code's is the one nobody expects. ARM 23.12.402(1) makes the Fire Prevention and Investigation Section, inside the Department of Justice, responsible for administering and enforcing the fire code "in every area of the state of Montana". Chief fire officials of each municipality, fire service area and organised fire district enforce inside their own limits and assist the FPIS; where no local fire inspection programme exists, MCA § 50-61-114(2) lets a Department of Justice fire inspector enter buildings and premises on the department's priority schedule. There is no opt-out for a town that never started a programme, which is the failure mode this pattern usually has. MCA § 50-3-102(4) adds the sharpest tool: the department may sue to enjoin the use of all or part of an existing building until it complies.

DPHHS runs the second track, through local environmental health departments and county sanitarians, inspecting licensed public accommodations annually as a condition of renewal. Under MCA § 50-51-105 the county attorney must prosecute when DPHHS furnishes evidence of a violation, and § 50-51-215 lets a local health officer refuse to validate a licence.

The third track, the landlord-tenant remedies in MCA Title 70, chapter 24, part 4, is a tenant's to use and does not reach transient hotel occupancy at all.

Penalties

Under MCA § 50-51-106, violation of Montana's hotel/motel/lodging chapter is a misdemeanor. Fines are: first offense $50-$100; second offense $75-$200; third and subsequent offenses $200 or more, with the possibility of imprisonment in the county jail. Operating without a required Public Accommodation License exposes the operator to license denial or revocation under the DPHHS licensing process. Under the landlord-tenant framework (MCA § 70-24-303), failure to install or verify a CO detector constitutes a breach of the landlord's statutory duty, which tenants may pursue under MCA Title 70, Chapter 24.

Local Override Warning

Montana closes one door before an operator starts looking. MCA 50-60-301(2)(a) provides that a county, city or town "may not adopt or enforce a building code that is more stringent than the building code adopted by the department or as required by state law", with one narrow exception for voluntary energy conservation incentives. That is among the tightest limits in this survey: most states let a city go stricter with findings or with state approval, and Montana does not allow it in the building code at all. The fire code is a separate instrument and it is where the room is, ARM 23.12.601 adopting the 2021 International Fire Code as the statewide minimum on which a city may build. So the local check here is a fire code check, plus whatever a registration programme attaches. The DPHHS Public Accommodation License is a statewide requirement; separate local permits or registration conditions may also apply. One local rule found in an August 2026 reading of seven Montana codes is worth planning around: Helena Section 13-2-7 amends the 2021 International Fire Code to require carbon monoxide detection in existing buildings under Section 1103.9 and to require carbon monoxide alarm signals to be transmitted automatically to a supervising station and to activate the occupant notification system. For a Helena property that means a monitored system rather than a shelf detector. How far that reaches is worth settling with the fire code official before ordering equipment: the same Helena section amends Section 907.6.6 to require fire alarm systems to be monitored by an approved supervising station under NFPA 72, and that amendment carries express exceptions for single- and multiple-station smoke alarms, for Group I-3 smoke detectors and for sprinklers in one- and two-family dwellings, while the carbon monoxide sentence carries no equivalent exception on its face. Billings, Missoula, Bozeman, Great Falls, Livingston and Whitefish add nothing, though Missoula's tourist home standards at Section 20.40.135 point operators back at the building code for smoke and carbon monoxide detectors. Kalispell, Red Lodge and West Yellowstone were not read. Verify with the relevant city or county before operating.

Frequently Asked Questions

Does Montana law require carbon monoxide detectors in hotels and motels?

Yes, through the state fire code rather than the rental statute. ARM 23.12.601 adopts the International Fire Code 2021 edition as Montana's minimum fire protection code, its amendment list never touches Section 915, and Section 915.1.1 covers Group R occupancies, which is where a transient hotel or motel sits. The trigger is a fuel-burning appliance or fireplace, a fuel-burning forced-air furnace, fuel-burning equipment elsewhere in the building with a communicating opening, or an attached private garage. Section 1103.9 carries the same duty into hotels already standing. On top of that, every Montana hotel needs a DPHHS Public Accommodation Licence under MCA Title 50, chapter 51, with annual inspection, and § 50-51-103(2) lets DPHHS make fire and life safety rules for licensed facilities.

Are Montana Airbnb and short-term rental hosts required to install CO detectors?

Yes, under two provisions. First, MCA § 70-24-303(1)(g) requires any landlord renting a dwelling unit, which includes most Airbnb and VRBO hosts, to install an approved CO detector when the unit has fuel-fired appliances or an attached garage. Second, Montana explicitly requires all short-term rentals, including Airbnb and VRBO listings, to obtain a DPHHS Public Accommodation License under MCA Title 50, Chapter 51. DPHHS's official public accommodations page confirms STRs are covered by the same licensing and inspection framework as hotels and motels.

Where must CO detectors be placed in a Montana guest room?

Inside it, as the default. IFC 2021 § 915.2.2, adopted by ARM 23.12.601 without amendment, says carbon monoxide detection "shall be installed in sleeping units", and the corridor placement is an exception available only where the guest room and its attached bathroom hold no fuel-burning appliance and no forced-air furnace serves them. The outside-the-sleeping-area rule that gets quoted for Montana comes from ARM 24.320.301, which is the Department of Labor and Industry's rule for let dwelling units, and its own text limits enforcement to the tenant remedies in MCA Title 70, chapter 24, part 4. Those remedies are unavailable to a hotel guest, because MCA § 70-24-104(4) excludes transient occupancy in a hotel or motel from the Act.

Who enforces Montana's CO detector rules for hotels and short-term rentals?

Two agencies, plus a tenant route that does not reach a hotel. The Fire Prevention and Investigation Section in the Department of Justice administers and enforces the fire code "in every area of the state of Montana" under ARM 23.12.402(1), with local fire chiefs enforcing inside their own jurisdictions and a state fire inspector entering where no local programme exists (MCA § 50-61-114(2)). MCA § 50-3-102(4) lets the department sue to shut all or part of an existing building until it complies. DPHHS runs the licensing inspection through county sanitarians, and under MCA § 50-51-105 the county attorney must prosecute when DPHHS furnishes evidence. The landlord-tenant remedies in MCA Title 70, chapter 24, part 4 belong to tenants, and § 70-24-104(4) puts transient hotel and motel occupancy outside that Act.

What are the penalties for non-compliance with CO detector rules in Montana?

Violating Montana's hotel and lodging licensing chapter (MCA Title 50, Chapter 51) is a misdemeanor under MCA § 50-51-106. Penalties are: first offense, a fine of $50-$100; second offense, $75-$200; third and subsequent offenses, $200 or more with possible imprisonment in the county jail. Additionally, DPHHS and local health officers may refuse to validate or renew a Public Accommodation License when safety requirements are not met. For operators who are also landlords under MCA § 70-24-303, failure to install a required CO detector constitutes a breach of the statutory duty to maintain the rental unit.

Can a Montana hotel or STR be all-electric and skip CO detectors?

Yes, but check against the fire code's trigger list rather than the rental rule's, because it is longer. IFC 2021 brings a room in on four conditions: a fuel-burning appliance or fireplace in the room, a fuel-burning forced-air furnace serving it, fuel-burning equipment anywhere in the building with a communicating opening to the room, and an attached private garage. The third of those catches properties that read as all-electric room by room while a gas boiler runs in the plant room. A property with electric heat, electric cooking, electric water heating, no wood-burning fireplace, no fuel-fired plant and no attached private garage is genuinely outside all of it. A wood stove in the lobby, a propane fire pit vented indoors or a gas dryer changes the answer.

Disclaimer: This page explains the law as it stood on August 24, 2026. It is general information, not legal advice, and reading it creates no attorney-client relationship. Requirements vary by city, county and building type, and statutes and codes are amended: confirm the current text with the issuing authority before acting on it. Each requirement here cites the instrument it comes from, so you can check it at source.

Sources and References

Montana Code Annotated § 70-24-303, Landlord duty to maintain premises; CO detector requirement in rental dwelling units , § 70-24-303(1)(g) (CO detector installation duty); § 70-24-303(5) (limitation of landlord liability)
Montana Administrative Rules ARM 24.320.301, Carbon Monoxide Detector Standard , ARM 24.320.301(1)(a) (placement outside each separate sleeping area); (1)(b) (UL 2034 standard and manufacturer's instructions); (2) (enforcement limited to MCA Title 70, Ch. 24, Part 4)
Montana Code Annotated Title 50, Chapter 51, Hotels, Motels, and Roominghouses; DPHHS Licensing and Penalties , § 50-51-103(2) (DPHHS rulemaking authority including fire and life safety); § 50-51-105 (county attorney prosecution); § 50-51-106 (misdemeanor penalties); § 50-51-215 (license refusal)
Mont. Admin. R. 23.12.601, adoption of the International Fire Code (2021 edition), and 23.12.402, enforcement , 23.12.601(1), (3), (4), (5)(ad) and (5)(ae); 23.12.402(1)
Montana Code Annotated § 70-24-104, exclusions from the Residential Landlord and Tenant Act , § 70-24-104(4)
Montana Department of Public Health and Human Services, Public Accommodations Licensing Program , Public Accommodations definition; licensing scope under MCA 50-51; physical requirements under ARM 37.111.1
Montana Code Annotated § 50-51-103, Department authorized to adopt rules for lodging , § 50-51-103(2) (fire and life safety rulemaking authority for hotels, motels, B&Bs, tourist homes)