Washington Carbon Monoxide Detector Laws: Every Home
Washington requires an alarm in every home, including one already lived in.
Washington requires an alarm in every home, including one already lived in.
Washington requires an alarm in every building classified as a residential occupancy, which reaches rentals and occupied homes rather than only new construction, and the one carve out is an owner occupied single family house legally occupied before July 26, 2009, which the seller must equip before anyone may occupy it after a sale.
In Washington 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, except for an owner occupied single family residence legally occupied before July 26, 2009, where it attaches when the house is sold.
Wash. Rev. Code 19.27.530, and what it attaches to
The sentence below is the whole of it. Everything that separates Washington 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
Carbon monoxide alarms, Requirements, Exemptions, Adoption of rules
Wash. 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.RCW 19.27.530, Washington State Legislature, read September 23, 2026. Read it at the source
- ReachEvery home, including one already lived in
- Triggernone: the duty is continuous, except for an owner occupied single family residence legally occupied before July 26, 2009, where it attaches when the house is sold
- EffectiveJanuary 1, 2011 for newly constructed residential occupancies and January 1, 2013 for all other residential occupancies
- SourceRCW 19.27.530, Washington State Legislature
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.
Washington 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.
| State | Effective | Citation | The sentence that attaches it |
|---|---|---|---|
| Washington | January 1, 2011 for newly constructed residential occupancies and January 1, 2013 for all other residential occupancies | Wash. 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 |
| California | July 1, 2011 for existing single family dwelling units and January 1, 2013 for all other existing dwelling units | Cal. 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 |
| Ohio | November 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 |
| Illinois | P.A. 94-741, eff. 1-1-07 | 430 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 |
| Alaska | not printed in the section | Alaska 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 |
| Iowa | not printed in the section | Iowa 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 |
| Massachusetts | not printed in the section | M.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 |
| Minnesota | not printed in the section | Minn. 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 York | not printed in the section | N.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 |
| Wisconsin | not printed in the section | 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.” source |
Washington writes the location into the code
Washington writes the spot into the code: outside of each separate sleeping area in the immediate vicinity of the bedrooms and on each level of the dwelling and in accordance with the manufacturer's recommendations. 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
outside of each separate sleeping area in the immediate vicinity of the bedrooms and on each level of the dwelling and in accordance with the manufacturer's recommendations
The rule reaches every storey, not only the sleeping floor.
R315.3 Location. Carbon monoxide alarms in dwelling units shall be installed outside of each separate sleeping area in the immediate vicinity of the bedrooms and on each level of the dwelling and in accordance with the manufacturer's recommendations. Where a fuel burning appliance is located within a bedroom or its attached bathroom, a carbon monoxide alarm shall be installed within the bedroom.Washington, read September 23, 2026. Read it at the source
What Washington puts on a landlord and what it puts on a tenant
Washington splits the job: the owner puts the alarm in and the tenant keeps it working. A rented dwelling is a residential occupancy and is covered with no sale needed, and the rules put battery replacement on the tenant.
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
a rented dwelling is a residential occupancy and is covered with no sale needed, and the rules put battery replacement on the tenant.
The rules adopted by the building code council under this section must (a) consider applicable nationally accepted standards and (b) require that the maintenance of a carbon monoxide alarm in a building where a tenancy exists, including the replacement of batteries, is the responsibility of the tenant, who shall maintain the alarm as specified by the manufacturer.Washington, read September 23, 2026. Read it at the source
Washington names the standard the alarm has to meet
Washington names the state building code, chapter 51-51 WAC, the Washington State Residential Code, section R315.
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.
The one other building the Washington code reaches
What the section covers in Washington is every building classified as a residential occupancy, with no fuel appliance or attached garage condition.
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.
homes being altered or added to under a permit
a permitted alteration, repair or addition, or a new sleeping room, triggers an inspection, and the pre July 2009 owner occupied house is excepted from that too
Wash. Admin. Code 51-51-0315, Section R315.2.1
Section R315.2.1. An inspection will occur where alterations, repairs, or additions requiring a permit occur, or where one or more sleeping rooms are added or created. EXCEPTIONS: 1. Work involving only the exterior surfaces of dwellings, such as the replacement of roofing or siding, or the addition or replacement of windows or doors, or the addition of a porch or deck, is exempt from the inspection requirements of this section. 2. Installation, alteration or repairs of nonfuel burning plumbing or mechanical systems or electrical systems are exempt from the inspection requirements of this section. 3. Owner-occupied single-family residences legally occupied before July 26, 2009. RCW 19.27.530 (2)(b).
Wash. Admin. Code 51-51-0315, Section R315.2.1, read September 23, 2026. Read it at the source
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.
| 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 |
Washington carbon monoxide alarm questions
Carbon monoxide detector laws in every state
Washington read September 23, 2026, off the state’s own published code: Wash. Rev. Code 19.27.530, 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 Washington 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.