Statutes Text, Article - Public Safety §12-1104, Maryland General Assembly was read on September 23, 2026, and every quote on this page came off that page on that day. Fifty states were read the same way for the national comparison.

Maryland Carbon Monoxide Detector Law and Where It Applies

Q: Does the Maryland requirement apply to a house that already exists?

Not on its own. The Maryland duty attaches to a building permit issued on or after January 1, 2008 for a dwelling that burns fossil fuel, or renting the dwelling out, which means a house that has not had that happen is not reached by the section. Ten of the fifty states wrote a duty that attaches to the dwelling itself instead.

Q: Where does Maryland say the alarm goes?

The code prints the spot: in a central location outside of each sleeping area; for a rental dwelling unit, outside and in the immediate vicinity of each separate sleeping area and on every level of the unit, including the basement. Maryland is one of 20 states that put a location in writing rather than leaving it to the manufacturer's instructions.

Q: What about buildings that are not houses in Maryland?

Maryland writes separate rules for hotels, lodging houses and rooming houses. Those sections sit beside the residential one rather than inside it, and each is quoted on this page.

Yes

Required in a home

Md. Code, Public Safety § 12-1104

Only on the trigger

Reaches a home already lived in

10 of the 42 states reach one

Covered

In a rented home

one of 28 states that reach a tenancy

In the code

Where the code says to put it

one of 20 states that print a spot

September 23, 2026

Read

off the state’s own published code

The short answer

Maryland requires an alarm in a rented home and in anything newly built.

Maryland requires a carbon monoxide alarm in a newly built dwelling that burns fossil fuel, in every rental dwelling unit, and in hotels and rooming houses, so a house built before 2008 that the owner lives in is outside the statute.

In Maryland the duty runs continuously in a rented home and otherwise waits for construction. The trigger the code names is a building permit issued on or after January 1, 2008 for a dwelling that burns fossil fuel, or renting the dwelling out.

Rented and newRented homesMd. Code, Public Safety § 12-1104read September 23, 2026

The section itself

Md. Code, Public Safety § 12-1104, and what it attaches to

The sentence below is the whole of it. Everything that separates Maryland from the state across the river sits inside that sentence and inside the clause that conditions it, which is why it is reproduced rather than summarised.

A requirement and the event it waits for are two different facts, and a roundup that carries the first without the second is how the same state gets described as strict and as lax in the same week. Both are on the card, with the citation, the title the code gives the section and the link the sentence was read from.

The section

Statutes Text, Article - Public Safety §12-1104, Maryland General Assembly

Md. Code, Public Safety § 12-1104

Except as provided in subsections (b) and (c) of this section, there must be a carbon monoxide alarm installed in a central location outside of each sleeping area within a dwelling subject to this subtitle.

Statutes Text, Article - Public Safety §12-1104, Maryland General Assembly, read September 23, 2026. Read it at the source

ReachRented homes, and anything newly built
Triggera building permit issued on or after January 1, 2008 for a dwelling that burns fossil fuel, or renting the dwelling out
EffectiveJanuary 1, 2008 for newly constructed dwellings; April 1, 2017 for hotels and lodging or rooming houses; April 1, 2018 for rental dwelling units
SourceStatutes Text, Article - Public Safety §12-1104, Maryland General Assembly

Two duties in one code: a landlord carries one all the time, and an owner occupier meets the other only by building.

Where the code says to put it

Maryland writes the location into the code

Maryland writes the spot into the code: in a central location outside of each sleeping area; for a rental dwelling unit, outside and in the immediate vicinity of each separate sleeping area and on every level of the unit, including the basement. The rule reaches every storey, not only the sleeping floor.

The rule is quoted below in the code's own words. Nationally 20 states print one and 5 of those reach every storey rather than the sleeping floor alone, and no two of the 20 are quite the same sentence.

Where the code puts it

in a central location outside of each sleeping area; for a rental dwelling unit, outside and in the immediate vicinity of each separate sleeping area and on every level of the unit, including the basement

The rule reaches every storey, not only the sleeping floor.

For a rental dwelling unit, on or after April 1, 2018, there must be a carbon monoxide alarm installed within the dwelling as follows: (1) outside and in the immediate vicinity of each separate sleeping area; and (2) on every level of the unit, including the basement.

Maryland, read September 23, 2026. Read it at the source

In a rented home

What Maryland puts on a landlord and what it puts on a tenant

Maryland reaches a rented home without naming which party carries the job. Every rental dwelling unit is covered from April 1, 2018, and the subtitle writes the duty passively rather than naming the landlord.

The split matters because the two halves are enforced differently: an installation duty runs against the owner and a maintenance duty commonly runs against whoever is living there. Where the section names no party, the card says so rather than filling the silence with the commonest answer. 28 states of the fifty reach a tenancy at all.

In a rented home

Installsnot named in the section
Maintainsnot named in the section

every rental dwelling unit is covered from April 1, 2018, and the subtitle writes the duty passively rather than naming the landlord.

For a rental dwelling unit, on or after April 1, 2018, there must be a carbon monoxide alarm installed within the dwelling as follows: (1) outside and in the immediate vicinity of each separate sleeping area; and (2) on every level of the unit, including the basement.

Maryland, read September 23, 2026. Read it at the source

What counts as an alarm

Maryland names the standard the alarm has to meet

Maryland names NFPA 720 for installation; ANSI/UL 217 and 2034 or ANSI/UL 268 and 2075 for a combined device. A combination smoke and carbon monoxide alarm is accepted. The section requires it hardwired.

38 states of the fifty name a standard and 16 say in writing that a combination smoke and carbon monoxide alarm satisfies the requirement. Where a state named none, approval belongs to the code the building is inspected under, which is a local reading rather than a state one.

Buildings that are not houses

The one other building the Maryland code reaches

What the section covers in Maryland is a newly built dwelling that burns fossil fuel, plus every hotel, rooming house and rental unit whatever it burns.

Hotels, schools, care homes and childcare buildings are where several legislatures started, and in a few states they are still the only place a carbon monoxide duty appears at all. Each is quoted below under the kind of building it covers.

hotels, lodging houses and rooming houses
alarms in guest rooms and areas near a carbon monoxide source or an enclosed attached garage, from April 1, 2017
Md. Code, Public Safety § 12-1104(b)
For a hotel or a lodging or rooming house, on or after April 1, 2017, there must be a carbon monoxide alarm installed within the dwelling, as follows: (1) on the wall inside each guest room that: (i) contains a device that emits carbon monoxide; (ii) is adjacent to a room or area that contains a device that emits carbon monoxide; (iii) is adjacent to an enclosed unventilated attached garage; or (iv) is connected by ductwork to an enclosed unventilated attached garage or room or area that contains a device that emits carbon monoxide; and (2) on a wall in each room or area that: (i) contains a device that emits carbon monoxide; (ii) is adjacent to a room or area that contains a device that emits carbon monoxide; or (iii) is adjacent to an enclosed unventilated attached garage.
Md. Code, Public Safety § 12-1104(b), read September 23, 2026. Read it at the source

How Maryland compares

The same question in the other forty nine

42 states require a carbon monoxide alarm in a home and 8 have no statewide section for one. Of the 42, 10 reach a home already lived in, 25 wait for a sale, a permit or a first build, and 28 reach a rented home.

The bar splits the fifty by what their section touches, and the table beneath it puts them in alphabetical order for finding a particular one. Neither order tracks how cold a state gets.

10Every home

4Rented and new

11Permit or new build

8Sale or transfer

6New build only

3Rented only

8None statewide

All fifty states, alphabetical. Reach is what the section speaks to: the dwelling itself, or an event happening to it.
State	Reach	Rented homes	Placement rule	Citation
Alabama	Permit or new build	No	No	Ala. Admin. Code r. 305-2-4-.09 (Residential Building Codes), adopted by the Alabama Energy and Residential Codes Board under Code of Ala. 1975, Sections 41-23-80 through 41-23-85
Alaska	Every home	Yes	Yes	Alaska Stat. 18.70.095(a)
Arizona	None statewide	No	No	No section
Arkansas	Permit or new build	No	No	12 CAR pt. 15, Arkansas Fire Prevention Code, 2021 Edition, Volume III
California	Every home	Yes	Yes	Cal. Health & Safety Code 17926(a)
Colorado	Sale or transfer	Yes	Yes	C.R.S. 38-45-102
Connecticut	New build only	No	No	Conn. Gen. Stat. §29-292
Delaware	Rented only	Yes	No	16 Del. C. 6602C
Florida	New build only	Yes	Yes	Fla. Stat. 553.885
Georgia	New build only	No	No	Georgia State Amendments to the International Residential Code (2024 Edition), Section R311 Carbon Monoxide Alarms, revising Section R311.2.1, adopted by the Department of Community Affairs under the Uniform Codes Act, O.C.G.A. Section 8-2-20 et seq.
Hawaii	Permit or new build	No	No	Haw. Rev. Stat. 107-25, with the code adopted under it
Idaho	New build only	No	No	Idaho Code 39-4116(2)(b), with the code itself defined at 39-4109(1)(b)
Illinois	Every home	Yes	Yes	430 ILCS 135/10
Indiana	Permit or new build	No	No	675 IAC 14-4.4-27 (2020 Indiana Residential Code, amending Section R315.2.2 of the 2018 International Residential Code)
Iowa	Every home	Yes	No	Iowa Code 10A.518(3)(b)
Kansas	None statewide	No	No	No section
Kentucky	New build only	No	No	815 KAR 7:125, promulgated under KRS 198B.040(7) and 198B.050
Louisiana	Sale or transfer	Yes	No	La. R.S. 40:1581
Maine	Sale or transfer	Yes	Yes	25 M.R.S. §2468
Maryland	Rented and new	Yes	Yes	Md. Code, Public Safety § 12-1104
Massachusetts	Every home	Yes	No	M.G.L. c. 148, §26F1/2
Michigan	Permit or new build	Yes	Yes	MCL 125.1504f (Stille-DeRossett-Hale Single State Construction Code Act, 1972 PA 230, Sec. 4f; the "Overbeck law")
Minnesota	Every home	Yes	Yes	Minn. Stat. 299F.51, subd. 1 (a)
Mississippi	None statewide	No	No	Senate Bill 2378, 2014 Regular Session, Section 1
Missouri	None statewide	No	No	No section
Montana	Rented only	Yes	No	Mont. Code Ann. 70-24-303(1)(g)
Nebraska	Sale or transfer	Yes	Yes	Neb. Rev. Stat. 76-604
Nevada	None statewide	No	No	No section
New Hampshire	Rented and new	Yes	No	RSA 153:10-a
New Jersey	Sale or transfer	Yes	No	N.J.S.A. 52:27D-133.3
New Mexico	Permit or new build	No	No	14.7.3 NMAC, 2021 New Mexico Residential Building Code
New York	Every home	Yes	No	N.Y. Exec. Law 378(5-a)
North Carolina	Rented and new	Yes	Yes	N.C. Gen. Stat. § 42-42(a)(7)
North Dakota	None statewide	No	No	N.D. Admin. Code 45-18-01-04
Ohio	Every home	Yes	Yes	Ohio Adm.Code 1301:7-7-11 (Ohio Fire Code, Chapter 11), modifying International Fire Code Sections 1101.1 and 1103.9
Oklahoma	Permit or new build	No	No	OAC 748:20-6-1
Oregon	Sale or transfer	Yes	Yes	Or. Rev. Stat. 105.838
Pennsylvania	Rented only	Yes	Yes	Carbon Monoxide Alarm Standards Act, Act of Dec. 18, 2013, P.L. 1229, No. 121, section 4
Rhode Island	Sale or transfer	Yes	Yes	Rhode Island Life Safety Code, 450-RICR-00-00-8, §24.6.3.1 (adopted under R.I. Gen. Laws §23-28.1-2)
South Carolina	Permit or new build	No	No	S.C. Code Regs. R.8-1200 (2021 International Residential Code as adopted), promulgated under S.C. Code Ann. Section 6-9-40 and Section 6-9-50
South Dakota	None statewide	No	No	No section
Tennessee	Permit or new build	No	No	Tenn. Comp. R. & Regs. 0780-02-23-.02 (Adoption by Reference), Division of Fire Prevention, under T.C.A. Section 68-120-101(a), (b), and (d)
Texas	Permit or new build	No	No	Tex. Loc. Gov't Code 214.212
Utah	Permit or new build	No	No	Utah Code 15A-2-103(1)(b)
Vermont	Sale or transfer	Yes	Yes	9 V.S.A. §2882
Virginia	New build only	Yes	Yes	13VAC5-63-240 (Virginia Construction Code, Section 915 as amended), adopted under Va. Code § 36-99
Washington	Every home	Yes	Yes	Wash. Rev. Code 19.27.530
West Virginia	Rented and new	Yes	Yes	W. Va. Code § 15A-10-12
Wisconsin	Every home	Yes	Yes	Wis. Stat. 101.647 (3) (a)
Wyoming	None statewide	No	No	No section

A row of tall nineteenth century brick and frame houses on Queen City Avenue in the South Fairmount neighbourhood of Cincinnati, under a clear sky. — Housing this old is the whole question. Ohio is one of ten states whose carbon monoxide section attaches to the dwelling itself, so it reaches these houses as they stand. In most of the country the same section would wait for one of them to be sold, altered under permit or rebuilt. “Queen City Avenue, South Fairmount, Cincinnati, OH (28224745388)”, Warren LeMay, CC0

Maryland carbon monoxide alarm questions

Does Maryland require a carbon monoxide detector?

Does the Maryland requirement apply to a house that already exists?

Where does Maryland say the alarm goes?

Who is responsible in a rented home in Maryland?

What about buildings that are not houses in Maryland?

What kind of alarm does Maryland accept?

When was this read?

Carbon monoxide detector laws in every state

Home heating rebatesWhat a state pays toward replacing the fuel burning appliance the alarm is watching, and where the application actually lives.Sidewalk snow removal rulesWho has to clear the walk and by when, read off thirteen statutes and a great many city codes.Leaving a car running unattendedThe winter law that turns out to sit in a theft statute rather than an emissions one.Ground snow load by stateWhat a roof is designed to carry, and the fourteen states that publish their own number.

Maryland read September 23, 2026, off the state’s own published code: Md. Code, Public Safety § 12-1104, as part of a reading of all fifty compiled September 23, 2026. Every quotation above is reproduced in the source’s own wording and links back to the document it was read from. Legislatures amend these between sessions, and a county or city building code can reach a building the state code does not, so the link beside a quote is what governs on the day. What Maryland wrote is what this page carries: the duty, what it attaches to, where the code puts the alarm, what it says about a rented home, and the sentence it set.