CO Detector Requirements in Maryland: Homes, Rentals, and Hotels

Last verified: August 26, 2026

Maryland carbon monoxide detector laws are governed by Public Safety sections 12-1101 through 12-1106 and apply across multiple occupancy categories, including covered homes, rental units, and lodging settings. The statutory framework combines applicability language, installation rules, and approved-device requirements, with local enforcement playing a major operational role.

Maryland requirements include location logic for sleeping areas and level-based placement in rental units, while hotel and rooming scenarios carry additional trigger language tied to adjacent risk conditions. Because statewide penalty language is less centralized, owners and operators should treat inspection readiness, documentation, and correction workflow as primary compliance controls.

The most defensible Maryland approach is section-by-section mapping of applicability, placement, and maintenance obligations before occupancy, turnover, or permit closeout. Maryland operators should maintain subsection-level records for each unit and occupancy type.

In 60 Seconds

CO detector requirements for Maryland
Applies to homes?	Yes
Applies to rentals?	Yes
Applies to hotels/STRs?	Yes
Applies to schools?	Yes, under a condition
Applies to workplaces?	Yes, under a condition

Schools and workplaces

Schools: it depends, and the test is one you can apply to the building itself. Maryland puts the school rule in the Education Article rather than beside its lodging rule, which is why a search of the carbon monoxide subtitle misses it. Education Article section 4-117 requires a building to be constructed or substantially remodeled to install approved carbon monoxide detectors in areas of new and existing educational occupancies where fuel fired equipment is present, installed in accordance with NFPA 720, Standard for the Installation of Carbon Monoxide Detection and Warning Equipment, 2009 edition, or as referenced in the State Fire Prevention Code. Two conditions run together there and both have to hold: construction or substantial remodelling as the occasion, and fuel fired equipment as the trigger. An all-electric school is outside it, and so is one that has not been remodelled. Note that the section reaches areas of new AND existing educational occupancies once the occasion arrives, so a remodelling project pulls the older parts of the building in with it. Public Safety 12-1104, the instrument that answers a Maryland hotel and rental dwelling unit, does not describe a classroom.

Workplaces: it depends, and the test is one you can apply to the building itself. Assembly is the one workplace Maryland's route reaches, and it reaches it through the Life Safety Code rather than through the carbon monoxide subtitle. Public Safety Article Title 12 Subtitle 11 works by naming building types - hotels and lodging houses at 12-1104(b), rental dwelling units at 12-1104(c) - and a workplace is not among them. What sits above that floor is COMAR 29.06.01.02B, which incorporates NFPA 101 Life Safety Code (2024 Edition), and NFPA 101 is organised by occupancy rather than by an occupancy-group list. Section 12.3.4.4.1 requires carbon monoxide detection and warning equipment in a new assembly occupancy in rooms holding permanently installed fuel-burning appliances or fireplaces, centrally within occupiable spaces served by the first supply air register from a permanently installed fuel-burning HVAC system, and centrally within occupiable spaces adjacent to an attached garage, with garages and open or mechanically ventilated parking excepted at 12.3.4.4.2. Section 13.3.4.4 carries the same rule to an existing assembly occupancy and is new in the 2024 edition, so a restaurant, bar, theatre or place of worship already standing is inside it. COMAR 29.06.01.07 amends NFPA 101 at length and does not touch 12.3.4.4 or 13.3.4.4, so the base text governs both. The business, mercantile, industrial and storage chapters require nothing, so an office, a shop, a factory and a warehouse remain outside. No International Code edition reaches Group A at all. Two Maryland amendments in .07 add a duty the model text does not carry, and they are workplaces in the ordinary sense: at 19.3.4.6 and 21.3.4.5 the state requires carbon monoxide detectors "on the ceilings of rooms containing permanently installed fuel-burning appliances, including fireplaces" in existing health care and existing ambulatory health care occupancies. Section 12-1106 authorises counties and municipal corporations to enact requirements more stringent than the state baseline, which is where a broader local workplace rule would sit.

When Are CO Alarms Required?

Buildings with fuel-burning appliances
New construction
When building permits are required
Public Safety 12-1102 includes newly constructed fossil-fuel dwellings with specified permit context and also includes hotel, lodging, rooming, and rental dwelling categories.
The §12-1102 newly-constructed-dwelling scope tier applies to dwellings that rely on fossil-fuel combustion for heat, ventilation, hot water, or clothes-dryer operation AND for which a building permit was issued on or after January 1, 2008. Hotels, lodging or rooming houses, and rental dwelling units fall under the separate occupancy tier regardless of construction date.

Where to Install CO Alarms

Central location outside each sleeping area within a dwelling under Public Safety 12-1104(a).
For rental dwelling units, outside and in the immediate vicinity of each separate sleeping area and on every level including basement under 12-1104(c).
For hotel, lodging, and rooming contexts, placement rules include listed guest-room and adjacency scenarios under 12-1104(b).
Alternative centralized system options are addressed in 12-1104(d).

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

Device Requirements

Approved alarms listed by nationally recognized testing laboratories accepted by Maryland State Fire Marshal framework.
Power options include AC with battery backup, sealed long-life battery options, or approved control-unit pathways as specified in 12-1101.
Combination smoke and CO devices are permitted when statutory listing standards are met.

Landlord and Tenant Responsibilities

Landlord: Rental owners must provide required alarm placement and operability under statutory placement sections. Provision: 12-1101.

Tenant: Public Safety 12-1105 binds any person, not occupants alone: except as part of routine maintenance, a person may not render a carbon monoxide alarm inoperable. A tenant is one such person, so removing, disconnecting or covering a required alarm is a statutory violation rather than a lease matter. Provision: Public Safety 12-1105.

Local jurisdiction procedures may add operational detail on inspections and corrective timelines.

Full Maryland landlord and tenant carbon monoxide duties, with citations

Enforcement

Enforced by: Local fire and building authorities implement enforcement in practice, with statewide statutory framework in Public Safety 12-1101 through 12-1106.

Enforcement typically occurs:

During local inspections, permit workflow, and occupancy compliance checks.
During follow-up actions where alarms are missing, inoperable, or improperly placed.

What a Tenant Can Do in Maryland

When a carbon monoxide alarm stops working in a rented home in Maryland, these are the five routes a tenant can take and where each one comes from.

"Via general law" means the Maryland carbon monoxide statute itself is silent and the remedy comes from the state's landlord-tenant law instead. The remedy is available even though the alarm rule does not contain it.

"No provision found" is a finding rather than a gap in the research: the chapter that would carry that remedy was read and contains nothing either way. What was read is named beside the row.

Tenant remedies for a defective carbon monoxide alarm in Maryland, with the citation or the body of law searched for each.
Rent withholding	Via general lawMd. Real Prop. 8-211. Two routes out of one section, and the second is rarer than the first. The tenant may bring a rent escrow action and pay rent into court, or may withhold and raise the condition as an affirmative defense when the landlord sues for rent or possession. Most states in either states offer one or the other. Maryland lets the tenant choose whether to move first or wait.
Repair and deduct	No provision foundSearched: Md. Code, Real Property, Title 8, Subtitle 2, centred on the rent escrow section at 8-211 and its list of tenant relief. Everything 8-211 offers is ordered by a court: escrow, rent abatement, an order that the landlord make repairs, or termination. Nothing lets a tenant hire the work done and take the cost off the rent. Maryland's answer to a defect is to move the money into court and let a judge direct it, which leaves a tenant who wants a $60 alarm replaced with a courthouse trip and no self-help alternative.
Right to end the lease	Via general lawMd. Real Prop. 8-211. Termination is one of the outcomes a court may order, together with return of the premises to the landlord and subject to the tenant's right of redemption. It is not something the tenant elects by serving notice, which separates Maryland from Virginia and Alabama, where a correctly drafted notice ends the tenancy on its own terms if the landlord does nothing.
Notice the tenant must give	Via general lawMd. Real Prop. 8-211. Three ways to satisfy it, and the third is the one to use. A written communication by certified mail listing the conditions, actual notice, or a written violation, condemnation or other notice from a State, county, municipal or local agency. That last route means an inspector's notice does the tenant's job, so a tenant who has already called code enforcement may have started the clock without writing anything.
Landlord cure period	Via general law, 30 daysMd. Real Prop. 8-211. The statute says reasonable time and then puts a thumb on the scale, with a rebuttable presumption that anything beyond 30 days from receipt of notice is unreasonable. Thirty is therefore a ceiling the landlord has to justify passing rather than a period the landlord is entitled to use, and for a hazard a much shorter time can still be unreasonable.

Applies to every row above:Maryland is not a URLTA state, and its remedies sit in one section, Real Property 8-211, which the state calls rent escrow and which does the work that four or five separate sections do in a URLTA act. The alarm duty lives elsewhere, in Public Safety 12-1101 and the sections after it, and it reaches every rental dwelling unit since 1 April 2018 without asking what the unit burns. Section 12-1102 applies the subtitle to two things: a newly constructed dwelling that relies on fossil-fuel combustion and holds a building permit issued on or after 1 January 2008, and, separately and with no condition attached, "a hotel, a lodging or rooming house, or a rental dwelling unit". Getting from that duty into 8-211 takes one step a reader should know about: the section's list of qualifying defects does not name carbon monoxide, so a dead alarm arrives through the catch-all for any condition presenting a health or fire hazard rather than as a listed item.

Remedies last checked 2026-08-03. Compare Maryland with the other states.

What Maryland Requires in Lodging

The Maryland carbon monoxide requirement reaches hotels and short-term rentals.

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

Operator duty: Maryland puts the alarm in the room and says so in the statute, which is rarer than it sounds. Public Safety 12-1104(b)(1) requires an alarm "on the wall inside each guest room" that contains a device emitting carbon monoxide, is adjacent to a room or area containing one, is adjacent to an enclosed unventilated attached garage, or is connected by ductwork to any of those. 12-1104(b)(2) adds an alarm on a wall in each room or area that itself contains such a device, is adjacent to one, or is adjacent to such a garage, so the plant rooms are covered as well as the guest rooms. The deadline was 1 April 2017 and there is no construction-date cutoff. 12-1104(d) offers one alternative: where a centralised alarm system can emit a distinct and audible sound warning all occupants, the owner may instead install an alarm within 25 feet of any carbon monoxide producing fixture or equipment. The rule at 12-1104(c), outside each separate sleeping area and on every level including the basement, is the rental dwelling unit tier and does not govern a hotel.

Full Maryland hotel and short-term rental requirements

Penalties for Non-Compliance

Maryland runs two tracks and only one of them carries a figure, which is why the answer looks absent from whichever track a reader opens first. The statutory requirement for dwellings sits in Public Safety Title 12, where 12-1105 prohibits rendering a required alarm inoperable and no section attaches a fine to it. The lodging requirement arrives through the State Fire Prevention Code instead, and that code has a penalty of its own: Public Safety 6-601(a) makes it unlawful to knowingly violate the title or a regulation adopted by the State Fire Prevention Commission, and 6-601(b) makes the violation a misdemeanor carrying imprisonment of not more than 10 days or a fine of not more than $1,000 or both. Section 6-317 treats each day a fire-hazard violation continues after the owner has knowledge or notice as a separate offense.

Md. Public Safety 6-601(a) and (b) for the misdemeanor, the 10 days and the $1,000, with 6-317 for the per-day rule. Public Safety 12-1105 and 12-1106 are the dwelling track and carry no fine.

Additional Notes

Maryland statewide text should be read with local enforcement practice and occupancy-specific interpretation.
The cited statewide sources do not equate all short-term rental models to a single statutory category without local classification review.

Local Rules That Differ From State Law

At least one Maryland municipality sets CO requirements that go beyond the statewide rule. Where your property sits decides which applies, and the stricter one governs.

Ocean City

Ocean City wrote its own carbon monoxide article in 2020, one of only two standalone municipal carbon monoxide articles in this survey and the longer of the two, the other being Crested Butte, Colorado's. Chapter 34 Article VI, added by Ordinance 2020-05 on 15 June 2020, sets minimum life safety requirements for detectors in all applicable residential occupancies inside the town. Start with reach, because Section 34-204(a) covers all new and existing multifamily dwelling units, not merely new ones. The triggers are the usual two plus a third that is unusually wide: a unit qualifies if it holds fuel-burning equipment, if it contains an enclosed parking area, or if it is merely adjacent to an enclosed parking area or to any room or space outside the dwelling units where fuel-burning equipment is installed or operated. A flat next to the boiler room is inside the ordinance whether or not anything burns inside the flat. Paragraph (4) then lets the fire marshal add areas by decision. Section 34-205 is where the detail sits. At least one detector goes on every level of a dwelling unit, in the immediate vicinity of and audible in all sleeping areas. At least one goes in the room or space holding the fuel-burning equipment, unless that space is under 24 square feet, in which case it goes immediately outside; no other jurisdiction in this survey draws the line by floor area. Detectors are required in plant rooms outside the dwelling units too. They must sound a distinctively different alarm from the smoke detectors in the same unit. In new multifamily buildings with a fire alarm system, detectors in the common spaces connect to that system and raise a supervisory signal at the panel; in new multifamily buildings over 50 feet tall, measured from the lowest point of fire department access to the highest occupiable floor, the detectors inside the flats do the same and must also sound through all sleeping areas of the flat. Paragraph (h) reaches the front desk. Every multifamily dwelling where detectors are required, whatever its size, must make a carbon monoxide detector for the deaf or hard of hearing available on request, and in hotels and motels a sign saying so has to be conspicuously displayed there. Section 34-206 puts installation, repair and replacement on the owner and requires testing and maintenance to NFPA 720. Separately, Section 10-141 adopts a property maintenance code carrying the in-bedroom rule where fuel-burning equipment sits in a bedroom or its attached bathroom, and an end-of-life replacement duty.

Ocean City Code Chapter 34 Article VI, Sections 34-201 to 34-206, Ord. No. 2020-05 (15 June 2020), with the property maintenance code adopted at Section 10-141 Checked 2026-08-10.

Baltimore County

Baltimore County puts the alarm inside its rental licensing machinery rather than beside it. Section 35-5-213.1 carries a carbon monoxide alarm requirement in the subtitle governing rental properties, with its own definition of the device as one that senses carbon monoxide and emits a distinct and audible sound when it does. Section 35-6-107, on the issue and scope of a rental housing licence, then lists carbon monoxide detectors among the three items a landlord self-certifies, beside interconnected smoke detectors and wood balcony railings, and routes dwellings of six units or fewer, larger dwellings that cannot self-certify, and apartment complexes that cannot, down a different path. So in this county the question is not only whether the alarm exists but whether the owner was entitled to certify it themselves.

Baltimore County Code Section 35-5-213.1, carbon monoxide alarms in rental properties, with Section 35-6-107 on rental housing licence issuance and scope Checked 2026-08-10.

Annapolis

Annapolis mandates a device type rather than a location. Section 17.40.440 sets the city's fire safety requirements for multifamily dwellings and provides that where fuel fired appliances are used, one of the required smoke detectors must be a combination smoke and carbon monoxide detector. That is a different instrument from a standalone alarm duty: it rides on the existing smoke detector obligation, so the count of devices does not change and the specification of one of them does. Section 17.44.090 then attaches the subject to the short-term rental licence, requiring compliance with applicable laws, regulations and guidance on smoke detectors, carbon monoxide detectors and lead-based paint, and requiring the Department to inspect all rooms and dwelling units on the premises before the licence issues.

Annapolis City Code Section 17.40.440, fire safety for multifamily dwellings, with Section 17.44.090 on short-term rental licensing Checked 2026-08-10.

What was checked:Maryland invites the local layer rather than tolerating it, which is why this state produces more than most. Public Safety Article Section 12-1106 expressly authorises counties and municipal corporations to enact carbon monoxide alarm requirements more stringent than the state baseline, and Section 9-701 lets local jurisdictions adopt their own fire prevention codes and penalties. Three of the four jurisdictions read have used that room, and the widest-reaching of them is the town with the most rented beds in the state. Read on 2026-08-10: Ocean City, Baltimore County, Annapolis and Prince George's County. The first three are below. Prince George's County returned nothing on carbon monoxide. Baltimore City is the significant gap: it is not carried by any of the six publishers this survey uses, and it is both the largest jurisdiction in the state and the one with the oldest housing stock, so treat this entry as covering the shore, the capital and one large county rather than Maryland generally. Montgomery County, Anne Arundel County, Frederick County, Carroll County and Garrett County sit on a second publisher and were not read in this sweep.

Local sweep last reviewed 2026-08-10.

Official Sources & References

COMAR 29.06.01, Maryland State Fire Prevention Code , 29.06.01.02B incorporation clause; Regulation .07, the NFPA 101 amendments (fire code, accessed 2026-08-26)
Read verbatim at .02B on 2026-08-26: the chapter "incorporates by reference NFPA 1 Fire Code (2024 Edition), except as amended in Regulations .08 and .09 of this chapter, and NFPA 101 Life Safety Code (2024 Edition), except as amended in Regulation .07 of this chapter." The chapter's own history shows .02B among the regulations amended on 23 June 2025 at 52:12 Md. R. 599, which is the amendment that moved the editions. Secondary and archived copies still show the 2018 editions, which is worth knowing to anyone checking this citation: the superseded figure survives in a 2024 Wayback capture of dsd.state.md.us. An archived copy of a state's own publication is a snapshot of the law on the day it was taken, and Maryland had already moved before that capture was consulted. What the correction unlocks is larger than the citation. The assembly route had been left open on the ground that "Maryland is on the 2018 edition, which no report reaches, so the bracket that closed Georgia does not close this". Maryland is on the same 2024 edition Georgia is, which NFPA's A2026 Second Draft Report reproduces, so the bracket does close it: 12.3.4.4 for a new assembly occupancy and 13.3.4.4, new in the 2024 edition, for an existing one. Regulation .07 also opened at this host, where it had previously returned banner text with the rule absent. It amends NFPA 101 from Section 2.2 through 42.8.3.4.1.3 and does not touch 12.3.4.4, 13.3.4.4, 28.3.4.7 or 29.3.4.6, so the base text governs each of them. It adds two duties the model text does not carry, at 19.3.4.6 and 21.3.4.5, each requiring carbon monoxide detectors "on the ceilings of rooms containing permanently installed fuel-burning appliances, including fireplaces" - existing health care and existing ambulatory health care. NFPA 101 chapters 28 and 29 are the chapters that also sit behind Illinois, West Virginia and Maine.
Maryland Public Safety 12-1101 (definitions and approved alarm framework) , 12-1101 (state code, accessed 2026-02-16)
Device, listing, and power-path framework for Maryland CO alarm requirements.
Maryland Public Safety 12-1102 (applicability) , §12-1102 scope: fossil-fuel newly-constructed dwelling with building permit issued on or after January 1, 2008 (one tier); hotel, lodging or rooming house, or rental dwelling unit (second tier, no construction-date cutoff) (state code, accessed 2026-05-17)
Core scope and trigger language for covered dwelling and lodging categories. Re-verified via Wayback Machine snapshot 2025-04-18 (live mgaleg.maryland.gov reachable via curl with a browser User-Agent but blocked to other automated fetchers).
Maryland Public Safety 12-1103 (combination devices) , 12-1103 (state code, accessed 2026-02-16)
Combination smoke and carbon monoxide device standards.
Maryland Public Safety 12-1104 (installation locations) , 12-1104 (state code, accessed 2026-02-16)
Detailed placement requirements for dwellings, rentals, and lodging contexts.
Maryland Public Safety 12-1106 (local authority) , 12-1106 (state code, accessed 2026-02-16)
Confirms local jurisdictions may enact more stringent laws.

Disclaimer: This page explains the law as it stood on August 26, 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.

Frequently Asked Questions

Which Maryland law sections govern carbon monoxide detector requirements?

Public Safety Article sections 12-1101 through 12-1106, and the division of labour between them is what a reader needs. 12-1102 sets the scope, 12-1104 sets the placement, and 12-1105 makes it an offence to render a required alarm inoperable. Reading only one of them produces a wrong answer, because 12-1102 lets a property in on two quite different tests and 12-1104 then gives that property a placement rule specific to its category rather than a general one. And the subtitle is not the whole of Maryland law on this. A school is answered by Education Article 4-117, which sits in a different article entirely, and the State Fire Prevention Code at COMAR 29.06.01 incorporates NFPA 1 and NFPA 101 in their 2018 editions alongside all of it.

What Maryland properties are most likely to trigger CO alarm obligations?

Public Safety 12-1102 sets two tests and only one of them turns on a date. A newly constructed Maryland dwelling is inside the subtitle where it relies on fossil-fuel combustion for heat, ventilation, hot water or a clothes dryer AND its building permit issued on or after 1 January 2008, so an older house that was never permitted after that date is outside this limb however it is heated. Hotels, lodging houses, rooming houses and rental dwelling units are inside on their category alone, with no construction date attached, which is why a 1950s Baltimore rowhouse let to a tenant is covered where the identical house next door lived in by its owner is not.

Where must alarms be placed under Maryland rules?

Find the subsection for the category first, because Maryland writes three different placement rules and they are not interchangeable. For a dwelling, 12-1104(a) asks for a central location outside each sleeping area. For a rental dwelling unit, 12-1104(c) is stricter on two counts at once, asking for one outside and in the immediate vicinity of each separate sleeping area, and one on every level of the unit including the basement. For a hotel, lodging house or rooming house, 12-1104(b) works from listed guest-room and adjacency situations rather than from a single position. 12-1104(d) then allows a centralised system in place of individual alarms in some configurations. A landlord who installs to the dwelling rule rather than the rental rule has usually missed the basement.

What happens if alarms are missing or inoperable in Maryland?

There is no carbon monoxide fine schedule in the Public Safety Article, and the route runs through the fire code instead. Public Safety 12-1105 makes it an offence to render a required carbon monoxide alarm inoperable. A violation of the State Fire Prevention Code's alarm requirements is prosecuted as a misdemeanour under Public Safety 6-601, carrying a fine of up to $1,000, imprisonment of up to ten days, or both. So the number a Maryland owner should expect to see is the fire code's, not the carbon monoxide subtitle's, and the enforcing officer is the local fire marshal rather than a housing inspector.

My Maryland home is all-electric. Do I still need a carbon monoxide alarm?

It turns on whether anyone rents the place, not on the wiring. Section 12-1102 gives the subtitle two reaches. The first needs a dwelling that "relies on the combustion of a fossil fuel for heat, ventilation, hot water, or clothes dryer operation" and is newly constructed under a permit issued on or after 1 January 2008. An all-electric house you own and live in fails that first half, and the statute does not reach it. The second reach names its occupancies and attaches no condition: "a hotel, a lodging or rooming house, or a rental dwelling unit". Nothing asks what the building burns or when it was built. So an all-electric flat that is let out is inside the subtitle, and 12-1104(c) has required an alarm outside each sleeping area and on every level including the basement since 1 April 2018. The same all-electric building is outside the statute while the owner lives in it and inside it the day it is rented. A hotel is in scope unconditionally, but 12-1104(b) places alarms by what is nearby, so an all-electric one with no attached garage can trigger no location at all. Sections 12-1101 to 12-1106 carry no electricity-only exemption anywhere.

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