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Carbon monoxide alarm requirements, read September 23, 2026

Wisconsin Carbon Monoxide Detector Laws: Every Home

Wisconsin requires an alarm in every home, including one already lived in.

Yes
Required in a home
Wis. Stat. 101.647 (3) (a)
Yes
Reaches a home already lived in
one of 10 states that do
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

Wisconsin requires an alarm in every home, including one already lived in.

Wisconsin requires a working carbon monoxide detector in the basement and on every floor level of a one or two family dwelling, including a dwelling built long before the law, unless the dwelling has no attached garage, no fireplace and no fuel burning appliance.

In Wisconsin the duty attaches to the dwelling itself, so it is on a house that was built, sold and lived in long before the section passed. The trigger the code names is none: the duty is continuous and the statute says in terms that it applies to a dwelling built before February 1, 2011 as well as after.

Every homeReaches a lived in homeRented homesWis. Stat. 101.647 (3) (a)read September 23, 2026

The section itself

Wis. Stat. 101.647 (3) (a), and what it attaches to

The sentence below is the whole of it. Everything that separates Wisconsin 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

101.647 Carbon monoxide detectors. (3) Requirements.

Wis. Stat. 101.647 (3) (a)

The owner of a dwelling shall install a functional carbon monoxide detector in the basement of the dwelling and on each floor level except the attic, garage, or storage area of each dwelling unit.
Wisconsin Statutes 101.647, Carbon monoxide detectors, Wisconsin State Legislature, read September 23, 2026. Read it at the source

The section speaks to the dwelling rather than to something happening to it, which makes it the only shape that reaches a house nobody is building, selling or renting.

Why this state is unusual

Wisconsin is one of 10 states whose duty follows the dwelling

In the other 25 states that require an alarm, the requirement waits: for a sale, for a permit, for a first build, for a lease. A house standing in one of those states, owned by the same person for twenty years, can sit outside its state’s carbon monoxide section entirely. That is not true here.

The other 9 written the same way are below, with the sentence each one used and the date it took effect, oldest first.

The ten states whose carbon monoxide duty attaches to the dwelling itself, oldest section first.
StateEffectiveCitationThe sentence that attaches it
WashingtonJanuary 1, 2011 for newly constructed residential occupancies and January 1, 2013 for all other residential occupanciesWash. Rev. Code 19.27.530“(1) By July 1, 2010, the building code council shall adopt rules requiring that all buildings classified as residential occupancies, as defined in the state building code in chapter 51-54 WAC, but excluding owner-occupied single-family residences legally occupied before July 26, 2009, be equipped with carbon monoxide alarms. (2)(a) The building code council may phase in the carbon monoxide alarm requirements on a schedule that it determines reasonable, provided that the rules require that by January 1, 2011, all newly constructed buildings classified as residential occupancies will be equipped with carbon monoxide alarms, and all other buildings classified as residential occupancies will be equipped with carbon monoxide alarms by January 1, 2013. (b) Owner-occupied single-family residences legally occupied before July 26, 2009, are exempt from the requirements of this subsection (2). However, for any owner-occupied single-family residence that is sold on or after July 26, 2009, the seller must equip the residence with carbon monoxide alarms in accordance with the requirements of the state building code before the buyer or any other person may legally occupy the residence following such sale.” source
CaliforniaJuly 1, 2011 for existing single family dwelling units and January 1, 2013 for all other existing dwelling unitsCal. Health & Safety Code 17926(a)“(a) An owner of a dwelling unit intended for human occupancy shall install a carbon monoxide device, approved and listed by the State Fire Marshal pursuant to Section 13263, in each existing dwelling unit having a fossil fuel burning heater or appliance, fireplace, or an attached garage, within the earliest applicable time period as follows: (1) For all existing single-family dwelling units intended for human occupancy on or before July 1, 2011. (2) For all existing hotel and motel dwelling units intended for human occupancy on or before January 1, 2017. (3) For all other existing dwelling units intended for human occupancy on or before January 1, 2013.” source
OhioNovember 20, 2025 (rule); the modified Section 1103.9 begins "On or before January 1, 2019, carbon…"Ohio Adm.Code 1301:7-7-11 (Ohio Fire Code, Chapter 11), modifying International Fire Code Sections 1101.1 and 1103.9“2. The provisions of Section 1103.9 shall apply to all existing occupancies identified in Section 1103.9.” source
IllinoisP.A. 94-741, eff. 1-1-07430 ILCS 135/10“Every dwelling unit shall be equipped with at least one approved carbon monoxide alarm in an operating condition within 15 feet of every room used for sleeping purposes.” source
Alaskanot printed in the sectionAlaska Stat. 18.70.095(a)“(a) Smoke detection devices shall be installed and maintained in all dwelling units in the state, and carbon monoxide detection devices shall be installed and maintained in all qualifying dwelling units in the state. The smoke detection devices must be of a type and shall be installed in a manner approved by the state fire marshal. The carbon monoxide detection devices must have an alarm and shall be installed and maintained according to manufacturers' recommendations.” source
Iowanot printed in the sectionIowa Code 10A.518(3)(b)“Existing single-family dwellings that have a fuel-fired heater or appliance, a fireplace, or an attached garage shall be equipped with approved carbon monoxide alarms.” source
Massachusettsnot printed in the sectionM.G.L. c. 148, §26F1/2“Every dwelling, building or structure, including those owned or operated by the commonwealth, occupied in whole or in part for residential purposes, that: (1) contains fossil-fuel burning equipment including, but not limited to, a furnace, boiler, water heater, fireplace or any other apparatus, appliance or device that burns fossil fuel; or (2) incorporates enclosed parking within its structure shall be equipped by the owner with working, approved carbon monoxide alarms in conformance with the requirements of the board of fire prevention regulations” source
Minnesotanot printed in the sectionMinn. Stat. 299F.51, subd. 1 (a)“Every single-family dwelling and every dwelling unit in a multifamily dwelling must have an approved and operational carbon monoxide alarm installed within ten feet of each room lawfully used for sleeping purposes.” source
New Yorknot printed in the sectionN.Y. Exec. Law 378(5-a)“Standards for installation of carbon monoxide detectors requiring that every one or two-family dwelling, or any dwelling accommodation located in a building owned as a condominium or cooperative in the state or any multiple dwellings shall have installed an operable carbon monoxide detector of such manufacture, design and installation standards as are established by the council.” source
Wisconsinnot printed in the sectionWis. Stat. 101.647 (3) (a)“The owner of a dwelling shall install a functional carbon monoxide detector in the basement of the dwelling and on each floor level except the attic, garage, or storage area of each dwelling unit.” source
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Where the code says to put it

Wisconsin writes the location into the code

Wisconsin writes the spot into the code: in the basement of the dwelling and on each floor level except the attic, garage, or storage area of each dwelling unit. 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 the basement of the dwelling and on each floor level except the attic, garage, or storage area of each dwelling unit

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

The owner of a dwelling shall install a functional carbon monoxide detector in the basement of the dwelling and on each floor level except the attic, garage, or storage area of each dwelling unit.
Wisconsin, read September 23, 2026. Read it at the source
In a rented home

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

Wisconsin splits the job: the owner puts the alarm in and the tenant keeps it working. The owner installs; the occupant maintains, and once the owner has written notice that a detector is not functional the owner has 5 days to make it work.

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

  • Installsowner
  • Maintainstenant

the owner installs; the occupant maintains, and once the owner has written notice that a detector is not functional the owner has 5 days to make it work.

Except as provided under par. (b), the occupant of the dwelling unit shall maintain any carbon monoxide detector in that unit.
Wisconsin, read September 23, 2026. Read it at the source
What counts as an alarm

Wisconsin names the standard the alarm has to meet

Wisconsin names an Underwriters Laboratories, Inc., listing mark. A combination smoke and carbon monoxide alarm is accepted.

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 Wisconsin code reaches

What the section covers in Wisconsin is any building containing one or two dwelling units, unless it has no attached garage, no fireplace and no fuel burning appliance.

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.

  • tourist rooming houses, bed and breakfast establishments and public buildings used for sleeping or lodging

    a separate section with its own installation, maintenance and forfeiture provisions, keyed to fuel burning appliances, forced air furnaces and attached private garages

    Wis. Stat. 101.149

    Except as provided in sub. (5), the owner of a residential building shall provide carbon monoxide detectors at the locations specified in par. (ax) as required under pars. (ag) to (at).
    Wis. Stat. 101.149, read September 23, 2026. Read it at the source
How Wisconsin 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.

All fifty states, alphabetical. Reach is what the section speaks to: the dwelling itself, or an event happening to it.
StateReachRented homesPlacement ruleCitation
AlabamaPermit or new buildNoNoAla. 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
AlaskaEvery homeYesYesAlaska Stat. 18.70.095(a)
ArizonaNone statewideNoNoNo section
ArkansasPermit or new buildNoNo12 CAR pt. 15, Arkansas Fire Prevention Code, 2021 Edition, Volume III
CaliforniaEvery homeYesYesCal. Health & Safety Code 17926(a)
ColoradoSale or transferYesYesC.R.S. 38-45-102
ConnecticutNew build onlyNoNoConn. Gen. Stat. §29-292
DelawareRented onlyYesNo16 Del. C. 6602C
FloridaNew build onlyYesYesFla. Stat. 553.885
GeorgiaNew build onlyNoNoGeorgia 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.
HawaiiPermit or new buildNoNoHaw. Rev. Stat. 107-25, with the code adopted under it
IdahoNew build onlyNoNoIdaho Code 39-4116(2)(b), with the code itself defined at 39-4109(1)(b)
IllinoisEvery homeYesYes430 ILCS 135/10
IndianaPermit or new buildNoNo675 IAC 14-4.4-27 (2020 Indiana Residential Code, amending Section R315.2.2 of the 2018 International Residential Code)
IowaEvery homeYesNoIowa Code 10A.518(3)(b)
KansasNone statewideNoNoNo section
KentuckyNew build onlyNoNo815 KAR 7:125, promulgated under KRS 198B.040(7) and 198B.050
LouisianaSale or transferYesNoLa. R.S. 40:1581
MaineSale or transferYesYes25 M.R.S. §2468
MarylandRented and newYesYesMd. Code, Public Safety § 12-1104
MassachusettsEvery homeYesNoM.G.L. c. 148, §26F1/2
MichiganPermit or new buildYesYesMCL 125.1504f (Stille-DeRossett-Hale Single State Construction Code Act, 1972 PA 230, Sec. 4f; the "Overbeck law")
MinnesotaEvery homeYesYesMinn. Stat. 299F.51, subd. 1 (a)
MississippiNone statewideNoNoSenate Bill 2378, 2014 Regular Session, Section 1
MissouriNone statewideNoNoNo section
MontanaRented onlyYesNoMont. Code Ann. 70-24-303(1)(g)
NebraskaSale or transferYesYesNeb. Rev. Stat. 76-604
NevadaNone statewideNoNoNo section
New HampshireRented and newYesNoRSA 153:10-a
New JerseySale or transferYesNoN.J.S.A. 52:27D-133.3
New MexicoPermit or new buildNoNo14.7.3 NMAC, 2021 New Mexico Residential Building Code
New YorkEvery homeYesNoN.Y. Exec. Law 378(5-a)
North CarolinaRented and newYesYesN.C. Gen. Stat. § 42-42(a)(7)
North DakotaNone statewideNoNoN.D. Admin. Code 45-18-01-04
OhioEvery homeYesYesOhio Adm.Code 1301:7-7-11 (Ohio Fire Code, Chapter 11), modifying International Fire Code Sections 1101.1 and 1103.9
OklahomaPermit or new buildNoNoOAC 748:20-6-1
OregonSale or transferYesYesOr. Rev. Stat. 105.838
PennsylvaniaRented onlyYesYesCarbon Monoxide Alarm Standards Act, Act of Dec. 18, 2013, P.L. 1229, No. 121, section 4
Rhode IslandSale or transferYesYesRhode Island Life Safety Code, 450-RICR-00-00-8, §24.6.3.1 (adopted under R.I. Gen. Laws §23-28.1-2)
South CarolinaPermit or new buildNoNoS.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 DakotaNone statewideNoNoNo section
TennesseePermit or new buildNoNoTenn. 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)
TexasPermit or new buildNoNoTex. Loc. Gov't Code 214.212
UtahPermit or new buildNoNoUtah Code 15A-2-103(1)(b)
VermontSale or transferYesYes9 V.S.A. §2882
VirginiaNew build onlyYesYes13VAC5-63-240 (Virginia Construction Code, Section 915 as amended), adopted under Va. Code § 36-99
WashingtonEvery homeYesYesWash. Rev. Code 19.27.530
West VirginiaRented and newYesYesW. Va. Code § 15A-10-12
WisconsinEvery homeYesYesWis. Stat. 101.647 (3) (a)
WyomingNone statewideNoNoNo 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

Wisconsin carbon monoxide alarm questions

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Wisconsin read September 23, 2026, off the state’s own published code: Wis. Stat. 101.647 (3) (a), 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 Wisconsin 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.