Carbon Monoxide Detector Laws by State

"Do I legally need a carbon monoxide detector?" is a common question, and the honest answer is: it depends on where you live and what type of property it is. In the U.S., CO alarm requirements are typically set by state law and building/fire codes, and they can be tightened further by cities, counties, or local fire authorities.

This page gives a safety-first overview of how carbon monoxide detector laws usually work, what situations most commonly trigger a requirement (rentals, home sales, new construction), and how to quickly verify the current rule for your specific address.

In 60 Seconds: What Most CO Alarm Laws Have in Common

Most U.S. carbon monoxide alarm requirements follow a similar pattern:

They focus on buildings where people sleep (single-family homes, apartments, hotels, and many short-term rentals).
They often apply when there is an attached garage or fuel-burning equipment (gas/oil/wood appliances), but some states require alarms more broadly.
They specify "approved/listed" alarms and sometimes require hardwired + battery backup in new construction.
They set responsibility rules for owners/landlords vs tenants (installation, testing, replacement).
Local rules can add stricter placement details than the state minimum.

Why CO Detector Laws Exist

Carbon monoxide (CO) is an odorless, colorless gas produced by incomplete combustion. Because you cannot reliably detect CO by smell or sight, alarms are a primary layer of protection. Many jurisdictions adopted CO alarm laws after preventable deaths in homes, apartments, and hotels.

When CO Alarms Are Commonly Required

Even if your state differs in the details, these triggers are common:

New construction and major remodels (especially where permits are pulled).
Sale or transfer of a property (often tied to inspection or certificate requirements).
Rental properties (landlord obligations before move-in and sometimes ongoing).
Hotels, dorms, and short-term rentals (sometimes statewide, sometimes local).
Homes with fuel-burning appliances or attached garages (a frequent scope definition).

CO Alarm Requirements: Top 10 States Comparison

CO alarm requirements comparison for 10 most-searched states
State	Homes	Rentals	Hotels / STR	Penalties
California	Yes	Yes	Yes	Yes
Texas	No	No	Conditional	Yes
New York	Yes	Yes	Yes	Yes
Florida	Yes	Yes	Yes	No
Illinois	Yes	Yes	Yes	Yes
Pennsylvania	No	Yes	Yes	Yes
Ohio	Yes	Yes	Yes	Yes
Georgia	Yes	Yes	Conditional	No
North Carolina	Yes	Yes	Yes	Yes
Michigan	Yes	Yes	Yes	Not established

Table shows 10 most-searched states. See each state page for detailed requirements, citations, and local exceptions.

All 51 Jurisdictions, Counted

Figures in this section are counted from our own jurisdiction records when this page is built, so they move when the research does and nothing here is typed by hand. National numbers for these questions are quoted widely and disagree with each other, which is the reason to publish a countable one.

Owner-occupied homes. 39 of the 51 US jurisdictions apply their carbon monoxide requirement to owner-occupied homes. 10 were checked and do not. 2 are not established here, Missouri and Tennessee, which is a gap in our research rather than a finding that nothing applies.
Rentals. 40 of the 51 US jurisdictions apply their carbon monoxide requirement to rented dwellings. 10 were checked and do not. One, Missouri, is not established here, which is a gap in our research rather than a finding that nothing applies.
Hotels and short-term rentals. 46 of the 51 jurisdictions reach hotels and short-term rentals outright. 5 more reach lodging only where a stated condition holds, and each names the test on its own page.
What a tenant can do about it. 22 of the 51 jurisdictions leave a tenant no repair-and-deduct route for a carbon monoxide fault: in 20 the relevant body of law was read and contains no such provision, and 2 refuse it outright.

The tenant-remedy matrix behind those pages holds 255 cells across 51 jurisdictions, and not one of them is unresearched: every cell carries a citation or a record of exactly what was read. The per-jurisdiction cells are on the rental laws hub, and each state's own page carries the statute behind its row.

Where a jurisdiction is described above as not established, that records a gap in our research rather than a finding that no requirement exists. Counting those as noes is the mistake that produces the national figures we cannot reconcile.

Rentals Are Covered on Their Own Hub

Landlord and tenant duties are not settled nationally and are not settled here. Which side installs, tests and replaces is a question each state answers differently, and it needs a page with room for fifty-one answers and the remedies behind them. That page is the rental CO detector laws hub, which carries the split for every jurisdiction where we have established it, and what a tenant can do when an owner does not comply.

Placement Rules: What "The Law" Says vs Manufacturer Instructions

Some laws specify general placement (for example, outside sleeping areas), while others reference code standards. Regardless, the safest baseline is to follow the alarm manufacturer's instructions and any local code requirements. If guidance conflicts, prioritize the stricter requirement and consult your local authority or a licensed installer.

Related guidance pages on this site:

Where to place a CO detector (best locations in homes and apartments).
CO detector placement height (does CO rise or fall?).
How many CO detectors you need (a practical room-by-room checklist).

Hotels and Short-Term Rentals (Airbnb, Vrbo, etc.)

Short-term rental rules can be confusing because you may have three layers: state law, city/county ordinances, and platform policies. A platform may require hosts to disclose whether smoke/CO alarms are present, but local law may set the actual minimum installation standard.

If you host or manage a short-term rental, reduce risk by:

Checking your state and local requirements for rentals/STRs (not the platform checklist alone).
Using listed combination alarms only if they meet requirements for both hazards (smoke + CO) where installed.
Documenting tests, battery changes, and end-of-life replacement dates.

How to Check CO Alarm Requirements for Your State and City

Use this verification order (fastest to most authoritative):

Your local fire department / building department (they often summarize what's enforced locally).
State fire marshal / state building code resources (official interpretations and bulletins).
State legislature / official code website (the underlying statute text).
Property management / landlord-tenant guidance for your state (useful, but verify against official sources).

A caveat on the first entry, which is also why it sits first. A fire or building department page describes what a city recommends. An adopted code section states what a city can require. Where the two disagree the code governs, and this site holds two cases where they did. The San Francisco Fire Department publishes guidance that the city requires carbon monoxide alarms in all dwelling units; no section of the fire code as adopted in San Francisco carries that duty, and the operative rule there is California Health and Safety Code 17926 with its fuel-burning appliance, fireplace and attached-garage triggers. In Ohio, Columbus Fire landlord guidance was reported as carrying a placement rule of its own, and nothing in the Columbus City Code supports it. Acting on department guidance costs a landlord an alarm. Citing it as a duty someone else owes leaves them with nothing to point at.

A second caveat, about the date on a local citation. A municipal section number can be exactly right and still point at nothing, because city councils repeal these provisions and the guides quoting them do not go back to check. Writers still cite Chicago Municipal Code 13-64-190 for a 40-foot placement rule; the City Council repealed the whole of Chapter 13-64 on 10 April 2019, and the current edition prints that chapter as RESERVED above an editor's note recording it. Juneau went the same way on 22 September 2025, when Serial No. 2025-26 deleted 19.04.R315.1 and 19.11.705.1, the two carbon monoxide sections the borough had carried since 2009. Anything published before those dates describes a section that has since stopped existing. Two questions settle it: what date does this edition of the code carry, and is the section still printed rather than reserved.

A third caveat, and it is the one to ask first. Before you open a city code, check whether your state lets a city write one. Several state legislatures have settled that question, and two of them settled it in opposite directions. Oregon bars every city and county from enacting or enforcing a local ordinance on the design, inspection, testing, maintenance, placement or location of carbon monoxide alarms, under ORS 476.725(4), so a landlord working across Portland and Bend meets one standard, and an empty result from an Oregon city code is a legal fact rather than a gap in the search. South Dakota's legislature ran the lever the other way: SDCL 11-10-12 lets a municipality amend any provision of the International Residential Code and forbids only requirements more stringent than the model, which puts deletion inside the permission. Spearfish used it: item (4) of its building code amendments reads, in full, "IRC Chapter 3, Section 315 Carbon Monoxide alarms is hereby deleted." The edition the city has adopted decides which rule that removes, and the South Dakota page sets out both readings. Read your own state statute for a pre-emption clause or a cap before you spend an evening in a municipal code.

Tip: laws can differ for single-family homes, multifamily buildings, rentals, and hotels, so search using the property type (for example, "rental property carbon monoxide detector requirements {state}").

Explore by Property Type or Situation

Rental CO Detector Laws

Landlord and tenant CO alarm obligations across all 50 states.

Hotel & Airbnb CO Detector Laws

Which code reaches a guest room, whether it reaches the hotel already standing, and the rule in every state written up here.

Hotel & Airbnb CO Safety

Operator duties, traveler checklists, and state-level hotel requirements.

Rental Compliance Check

Answer a few questions to see which CO alarm rules likely apply to your rental.

Travel CO Safety Check

Staying somewhere new? Check your CO safety basics before you arrive.

Carbon Monoxide Detector Laws by State (A-Z)

Browse state summaries here (overview + rental/landlord notes where available):

A

C

D

I

K

L

Louisiana CO detector laws rental rules hotels and Airbnbs

O

P

Pennsylvania CO detector laws landlord duties lodging duties

R

Rhode Island CO detector laws rental rules hotels and Airbnbs

S

T

U

Utah CO detector laws landlord duties lodging duties

V

W

Specialized CO Law Guides

For requirements that apply specifically to rental properties or hotels and short-term rentals, see our dedicated guides:

CO Detector Laws for Rentals, landlord and tenant requirements by state.
CO Detector Laws for Hotels and Short-Term Rentals, which instrument reaches a guest room in each state and whether it reaches an existing building.
CO Safety in Hotels and Airbnbs, operator duties, traveler checklist, and state-level hotel requirements.

If a CO Alarm Sounds, Safety Beats Compliance

Legal requirements help prevent tragedy, but they don't replace immediate safety action. If an alarm sounds or anyone has symptoms, leave the building and seek help. Do not ignore an alarm because you're "not sure the law applies."

Related emergency guides:

What to do if a carbon monoxide detector goes off (step-by-step).
CO detector beeping (chirps vs alarm patterns and what they mean).

Frequently Asked Questions

Do you need a carbon monoxide detector if you have all-electric appliances?

Often yes, because many requirements are written around the attached garage rather than the appliances. Of the 51 US jurisdictions in our records, 31 name an attached garage as a trigger in its own right, so an all-electric house with a garage can fall inside the rule with no fuel-burning appliance anywhere in the building. Washington states it plainly: an all-electric dwelling still falls within the requirement when it has an attached garage. Check your own state page, and treat an alarm as a low-cost safety layer regardless of what the rule says.

Are CO detectors required in apartments and condos?

In 40 of the 51 jurisdictions we have established, the requirement reaches rented dwellings, which covers most apartments. Condominiums are less uniform, because the duty can sit with the association, the unit owner or a landlord depending on how the building is governed and who the occupant is. What varies most is not whether an alarm is required but who has to install and replace it, and that split is set state by state. Our rental hub carries the split and the tenant remedies for each jurisdiction.

Are CO alarms required in hotels?

More often than the figures in circulation suggest. Counting our own records, 46 of the 51 jurisdictions reach hotels and short-term rentals outright and 5 more reach lodging where a stated condition holds, such as the building's height or whether the property sits inside a city limit. Travel coverage repeats a much lower number, and it is not one we can reproduce from the instruments. Each state page names the condition and the code section behind it, so an operator can settle their own property rather than rely on a national count.

What happens if you don't have a required CO detector?

It depends on the jurisdiction, and the range is wide, which is why this answer stays general. Of the jurisdictions in our records, 32 carry a penalty provision we have identified; elsewhere the consequence arrives through inspection failure, a withheld certificate of occupancy, a rental licensing problem, or liability after an incident rather than through a fine written into the detector statute. Several states also give a tenant a remedy of their own. Treat compliance as a safety baseline and read your state page for what applies where you are.

Is a plug-in CO detector legal?

This one varies by jurisdiction and no single number settles it. Some jurisdictions accept plug-in alarms with battery backup, others require hardwired units with battery backup in new construction, and many accept battery-only devices in existing buildings while requiring hardwiring in anything newly built or substantially renovated. The device also has to be listed to the standard the jurisdiction names, most often UL 2034, and installed in the locations the code specifies. Check the device requirements section of your own state page before buying.

Sources & Verification

Behind the counts above sit 334 source entries across the 51 jurisdiction records. Each names the document, the section the answer turns on, and the date somebody opened it. All 334 carry that accessed date. It is the least glamorous field in the record and the one that decides whether a legal page is still worth anything a year after publication, which is why the national counts in circulation, none of which publishes one, cannot be checked at all.

By instrument: 156 state code, 60 fire code, 54 building code, 43 agency guidance, 13 secondary index, 8 local ordinance. 321 of the 334 are primary, meaning statute, adopted code or the agency's own guidance. The secondary indexes are the exception and they are not load-bearing: where one appears it is there to show where a widely quoted figure came from, never to support a finding of ours.

You do not have to take that on trust. Every state page prints its own sources with those dates attached, so pick your own jurisdiction and read them, or start with Colorado, where the statute, the Secretary of State's rule PDF and the adopted code appear as three separate entries because they answer three different halves of the question.

For anything you are about to act on, verify against your own jurisdiction using the order set out above, and treat a local ordinance as capable of overriding everything on this page. National resources worth keeping open while you do:

NFPA, Carbon Monoxide Safety, the fire protection standards and alarm guidance most state codes point back at. NFPA 72 itself is readable free in a read-only viewer with an NFPA account, which is more than the alarm standard allows.
CPSC, CO Information Center, federal consumer safety data and recalls. Incident counts, not law.
NCSL, CO Detector State Statutes, the most-cited cross-state legislative index and the right thing to read our per-jurisdiction records against. Where it and our record disagree, our state page shows its citation and its accessed date so you can settle it yourself.
ICC, International Code Council, the model building and residential codes most states adopt, and the reason the edition year your state adopted matters as much as the section number.

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.

Page last updated: August 26, 2026