What Wisconsin Requires for CO Detectors in Homes and Lodging

Last verified: August 24, 2026

Wisconsin splits its carbon monoxide rule across two statutes. Section 101.149 reaches residential buildings and lodging and sets no construction-date limit, which is what puts an existing property inside it, while section 101.647 is where the owner and occupant duties sit. SPS 328 carries the administrative detail and DSPS the guidance behind it. Covered dwelling and lodging contexts generally require functional detectors by floor level, with exemptions tied to the absence of attached-garage, fireplace, or fuel-burning source conditions.

Wisconsin also addresses tampering and ongoing functionality, which means compliance is not only an installation event but a continuing operations duty for owners and occupants in covered units. The practical control model is routine testing, documented notice and response workflow, and turnover verification before occupancy changes.

Wisconsin operators should keep statute and code references together with device maintenance records for each covered property. Logging exemption determinations and periodic review dates also supports ongoing audit continuity.

In 60 Seconds

CO detector requirements for Wisconsin
Applies to homes?	Yes
Applies to rentals?	Yes
Applies to hotels/STRs?	Yes
Applies to schools?	Yes, under a condition
Applies to workplaces?	No

Schools and workplaces

Schools: it depends, and the test is one you can apply to the building itself. Wisconsin used to substitute the model section and stopped. Chapter SPS 362 moved from the 2015 edition of the International Building Code to the 2021 with effect from 1 September 2025, and SPS 362.0915 did not come with it. The insert pages the Department of Safety and Professional Services publishes for the 2021 code carry SPS 362.0901, .0903, .0904, .0907, .0909, .0912 and .0913 and no .0915 at all, and the cross-reference to Wis. Stat. 101.149(2) that the old section turned on appears nowhere in them. So the model Section 915 is now in force in Wisconsin unamended, and it brings a limb the substituted text never had. Section 915.1.1 requires carbon monoxide detection in "Group I-1, I-2, I-4 and R occupancies and in classrooms in Group E occupancies" in the Section 915.2 locations where any of the conditions in Sections 915.1.2 through 915.1.6 exists. A Wisconsin classroom is therefore covered where it holds a fuel-burning appliance or fireplace, is served by a fuel-burning forced-air furnace, sits in a building holding such equipment with an opening that communicates, or adjoins an attached private garage. An all-electric school with no attached garage meets none of them. The occupancy limb is not the only thing Wisconsin gained when the substitution lapsed. Section 915.2.3 covers the same classrooms and does not stop at the device: the alarm signals must be "automatically transmitted to an on-site location that is staffed by school personnel", unless the Group E occupancy has an occupant load of 30 or less. The repealed SPS 362.0915 set device standards, hardwiring and a sealed-combustion exemption and carried nothing of the kind, so a Wisconsin district that treated the old section as the whole building-code duty is now short a monitored signal path as well as short a classroom trigger. The statute is untouched and still runs alongside. Wis. Stat. 101.149 reaches residential buildings on its own terms, and 101.149(1)(b) defines a residential building by sleeping or lodging use, which a school building is not. What changed is not the statute but the code that used to point at it in place of the model text. One date to check before relying on this. The department delayed the plan-compliance deadline, so plans submitted on or after 1 November 2025 must comply with the updated code. A project reviewed before then was reviewed against the 2015 code with SPS 362.0915 in it, where no classroom limb existed.

Workplaces: Wisconsin places no carbon monoxide detection duty on an office, shop or other workplace. Federal and state occupational rules set an exposure limit for carbon monoxide in air; they do not require a detector to be installed, and this row is about installation. Two instruments and neither reaches a place of work, though the reason on the code side has changed. Chapter SPS 362 now adopts the 2021 International Building Code, from 1 September 2025, and it no longer carries the SPS 362.0915 substitution that used to replace Section 915: the department's insert pages for the 2021 code run SPS 362.0901 through .0913 with no .0915 among them. So the model text governs, and Section 915.1.1 reaches Group I-1, I-2, I-4 and R occupancies and classrooms in Group E occupancies, with no Group B, F, M or S. An office, shop or factory is outside it. Wisconsin has not reached the 2024 edition, which is the one that would move this answer, because code change F102-21 replaces the occupancy list with a test on whether the building holds a carbon monoxide source. On the statutory side nothing has changed. Wis. Stat. 101.149 reaches residential buildings, and 101.149(1)(b) defines the term by sleeping or lodging use, taking in public buildings so used, tourist rooming houses and bed and breakfast establishments. ATCP 72.18(12) is the lodging licensing rule and reaches individually keyed units in a lodging facility. Neither describes a workplace.

When Are CO Alarms Required?

Buildings with fuel-burning appliances
Buildings with attached garages
Wisconsin statutory and SPS 328 pathways include exemptions when listed carbon monoxide source conditions are absent.

Where to Install CO Alarms

In covered dwellings, detectors are required in the basement and on each floor level except attic garage and storage-only areas.
Agency guidance for SPS 328 references sleeping-area proximity and floor-level coverage in covered residential settings.

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

Device Requirements

Functional detector devices consistent with Wisconsin statute and administrative code requirements.
When directly wired, backup battery pathways are required in cited Wisconsin code materials.
Device labeling and testing should follow recognized standards referenced in Wisconsin regulatory text and manufacturer instructions.

Landlord and Tenant Responsibilities

Landlord: Owners must install required detectors and respond to written notice when required detectors are nonfunctional in covered settings. Provision: 101.647.

Tenant: Occupants who are not owners are responsible for maintenance duties and written notice when detectors are not functional under cited rule language. Provision: 101.647.

Applicability to short-term rental properties should be verified against current occupancy definitions and local enforcement practice.
Wis. Stat. 101.149 carries no construction-date limit, which is what puts an existing Wisconsin lodging property inside it. 101.149(1)(b) defines "residential building" as a tourist rooming house, a bed and breakfast establishment, or any public building used for sleeping or lodging purposes, excluding only hospitals and nursing homes. 101.149(2)(ac) puts a standing duty on the owner of such a building to provide detectors, and 101.149(3)(a) to maintain every one of them. The contrast that settles it sits in the neighbouring section: 101.145(4), for smoke detectors, reaches an owner "the initial construction of which is commenced before, on or after May 23, 1978", so this legislature writes a construction-date clause when it wants one and wrote none here.

Full Wisconsin landlord and tenant carbon monoxide duties, with citations

Enforcement

Enforced by: Local building and code officials with state program oversight in applicable occupancy contexts.

Enforcement typically occurs:

During code inspection, complaint response, or occupancy safety review for covered properties.
During follow-up after written notice of missing or nonfunctional required detectors.

What a Tenant Can Do in Wisconsin

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

"Via general law" means the Wisconsin 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 Wisconsin, with the citation or the body of law searched for each.
Rent withholding	Via general lawWis. Stat. 704.07(4). Partial rather than total, and the statute says so in terms: rent abates to the extent the tenant is deprived of the full normal use of the premises, and the subsection does not authorize rent to be withheld in full while the tenant remains in possession. That is a cap on a remedy rather than the flat bar North Carolina and Alabama impose, so a Wisconsin tenant keeps something where those tenants keep nothing. The same subsection states it does not create a private cause of action.
Repair and deduct	No provision foundSearched: Wis. Stat. Chapter 704 (Landlord and Tenant), centred on the repairs and untenantability section at 704.07, together with the carbon monoxide section at 101.149. Neither chapter gives the tenant a way to do the work and take the cost off the rent. What 704.07(4) offers instead is abatement measured by lost use, which compensates for the defect rather than fixing it, and 101.149 speaks only to the owner's duty to maintain.
Right to end the lease	Via general lawWis. Stat. 704.07(4). The tenant may remove where the premises become untenantable through a condition hazardous to health, or a substantial violation of the landlord's repair duty materially affecting health or safety, unless the landlord proceeds promptly to repair or eliminate the hazard. Removal is also available where the nature and period of the repair would impose undue hardship. A tenant who justifiably moves out owes no rent after the premises became untenantable and gets back advance rent apportioned to that period.
Notice the tenant must give	Yes, in the CO rule, 5 daysWis. Stat. 101.149(3)(b) and 101.647(3)(b). Both carbon monoxide sections expressly let an occupant give the owner written notice that a detector is not functional, and 101.149(3)(b) adds a second limb worth knowing: it also covers a detector removed by a person other than the occupant, which is the case where a previous tenant or a contractor took the device away. The notice starts the five days. The form is the part to get right, because both sections say written, so a telephone call to the landlord starts nothing.
Landlord cure period	Yes, in the CO rule, 5 daysWis. Stat. 101.149(3)(b) and 101.647(3)(b). Five days from receipt of the occupant's written notice, and the two sections word the duty differently in a way that favours the tenant of a lodging or multi-tenant building. 101.149(3)(b) requires the owner to "repair or replace the nonfunctional or missing carbon monoxide detector within 5 days after receipt of the notice", so a device that has gone missing is squarely covered. 101.647(3)(b) gives the same five days for "any maintenance necessary to make that carbon monoxide detector functional", on notice from an occupant or from an official with property inspection powers. The separate limb at 101.149(3)(am), five days from a person certified under 101.12(4) or 101.14(4r), is an additional route to the same deadline rather than the only one. Where the defect makes the premises untenantable the standard also becomes 704.07(4)'s requirement that the landlord proceed promptly, which is a test rather than a date.

Applies to every row above:Wisconsin is not a URLTA state; Chapter 704 is its own landlord-tenant law and the carbon monoxide duty sits outside it, in two freestanding sections of the safety and professional services chapter. Which one reaches a given rental turns on a definition worth checking. Wis. Stat. 101.647 governs a dwelling. Wis. Stat. 101.149 governs a residential building, and 101.149(1)(b) defines that as a tourist rooming house, a bed and breakfast establishment or any public building used for sleeping or lodging, while 101.01(12) defines a public building to include any structure used by the public "or by 3 or more tenants". A three-unit building is therefore inside both. On the number that decides the two cells below the two sections agree: 101.647(3)(b) and 101.149(3)(b) each run five days from the occupant's own written notice, and 101.149(3)(am) attaches the same five days to an inspector's. There is no path on which a Wisconsin tenant's written notice starts nothing.

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

What Wisconsin Requires in Lodging

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

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

Operator duty: Wisconsin puts the lodging rule in its licensing chapter rather than in a code, and the placement is Wisconsin's own drafting rather than a model code's. ATCP 72.18(12) requires a carbon monoxide alarm for each individually keyed unit that contains a fuel-burning appliance, for each unit in a lodging facility that contains one where a communicating opening connects them, and for each unit with an attached private garage, and then places the alarm outside each separate sleeping area within 21 feet of any door to a sleeping room measured along a path of travel, plus inside a sleeping room where the appliance is in that room or its attached bathroom. Alarms conform to UL 2034, are installed to the manufacturer's directions, and are replaced by the manufacturer's expiry date, with notice to the department within five calendar days of a repair or replacement after being told of a non-functional or expired unit. One exception covers the whole subsection: it does not apply where every fuel-burning appliance in the lodging facility is a sealed combustion appliance covered by the manufacturer's warranty against defects.

Full Wisconsin hotel and short-term rental requirements

Penalties for Non-Compliance

Wis. Stat. 101.149(8) puts the figures in the carbon monoxide section itself. Where an inspection finds the owner has broken the installation duty in subsection (2) or the maintenance duty in subsection (3), the department orders correction within five days or less, and an owner who misses that deadline forfeits $50 for each day the violation continues after the department finds it uncorrected. Tampering is punished far harder: a first offense under subsection (4) carries a fine of up to $10,000 or nine months in jail or both, and a second is a Class I felony. One paragraph is worth knowing before budgeting for a large building. Under 101.149(8)(b), multiple violations found in a single inspection of one building count as one violation for the purpose of the forfeiture, so twelve missing detectors in one property produce one $50 daily charge rather than twelve.

Wis. Stat. 101.149(8)(a) for the daily forfeiture, (8)(b) for the single-violation rule, and (8)(c) for the tampering offenses. Read in the 2023-24 Wisconsin Statutes as published 1 January 2025.

Additional Notes

Wisconsin compliance should be documented by occupancy type because requirements and enforcement channels can differ.
Owners and managers should maintain written notice and response logs for nonfunctional detector reports.

Local Rules That Differ From State Law

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

Madison

Madison is the only jurisdiction in this survey that publishes what a missing carbon monoxide detector is worth in money. Section 32.04 of the ordinances is a rent abatement schedule, and item 41 prices the failure by where the missing device should have been: 5 to 10 percent of rent per affected area for a detector missing in the basement, 10 to 25 percent for one missing on a floor level other than an attic, garage or storage area, 10 to 25 percent for one missing outside a separate sleeping area in the immediate vicinity of the sleeping units, and a further band where a fuel-burning appliance sits inside a sleeping room. A Wisconsin tenant reading the statute learns that the landlord owes a detector; a Madison tenant learns what the rent should drop by until one appears, which is a different and much more usable kind of answer. Madison also attaches the duty to a housing type the state rules do not name. Section 28.151(b), in the zoning subchapter for tiny houses, requires every tiny house to have a smoke detector, a carbon monoxide detector and a fire extinguisher, and paragraph (c) restricts heating to listed vented gas appliances, liquid propane or natural, or electric heat. A dwelling too small to trigger much of the ordinary code still owes the alarm here.

Madison General Ordinances Section 32.04 item 41, rent abatement for carbon monoxide detectors not installed where required under Section 29.19(a), with Section 28.151(b) for tiny houses Checked 2026-08-10.

Kenosha

Kenosha cuts the state's repair deadline from five days to one. Wisconsin gives an owner five days to restore a detector to working order after written notice from an occupant. Section 16.25(B)(2) of Kenosha's property maintenance code gives the Responsible Person twenty-four hours from receipt of the occupant's written notice that a carbon monoxide detector is not functional or has been removed by somebody other than the occupant. On a weekend that is the difference between a device replaced on Saturday and one replaced the following Thursday. The rest of Section 16.25(B) is a complete small scheme rather than a single duty. Paragraph 1 requires the Responsible Person to maintain every detector in the manner the instructions specify. Paragraph 3 answers the objection that always follows a hard deadline by shielding the Responsible Person from damages for a false alarm from a reasonably maintained detector, and for a failure caused by someone else tampering with, removing or destroying the device, or by a faulty detector that was reasonably maintained. Paragraph 4 forbids anyone tampering with, removing, destroying, disconnecting or taking the batteries from an installed detector except during inspection, maintenance or replacement. Paragraph 5 keeps the state's exemption shape, excusing detectors where the building has no attached garage and no fuel-burning appliances.

Kenosha Code of General Ordinances Section 16.25(B), Chapter XVI Property Maintenance Code, fire safety requirements Checked 2026-08-10.

What was checked:Six municipalities read on 2026-08-10: Madison, Milwaukee County, Green Bay, La Crosse, Kenosha and Sturgeon Bay. Madison and Kenosha are below. Green Bay carries nothing. Three of the six do the same harmless thing and it should not be mistaken for a local rule. Madison Sections 29.22 and 34.01, and Sturgeon Bay Section 6.17, adopt SPS 328, the state's Smoke Detectors and Carbon Monoxide Detectors chapter, by reference alongside the rest of the state code family. That is adoption, not divergence, and Minneapolis did the same thing in Minnesota. Two more regulate the gas rather than the alarm: Madison Section 30.20 forbids leaving a gas conversion burner in operation unless it is adjusted so the products of combustion contain no more than 0.04 percent carbon monoxide, sampled from the breeching as near the furnace as possible, and La Crosse Section 103-200 sets the same 0.04 percent ceiling for gas burner installations of 400,000 BTU and smaller. Savannah's wick-heater rule is the third member of that family in this dataset, and none of the three requires a detector. On pre-emption, one honest limit. Wis. Stat. 101.149 does not appear to carry a clause about local ordinances, and the general limit on municipalities making the Uniform Dwelling Code more restrictive could not be read from a primary source on 2026-08-10, because docs.legis.wisconsin.gov refused connections and Justia answered 403. Worth noting that both findings below sit in a property maintenance chapter and a landlord-tenant chapter rather than in the dwelling code, which is where they would have to be if that limit does apply. Milwaukee city, Appleton, Wisconsin Dells and the Door County lake towns were not searched.

Local sweep last reviewed 2026-08-10.

Official Sources & References

Wisconsin Statutes section 101.647 , 101.647(3)(a) for the basement-and-each-floor-level rule and the backup battery, 101.647(3)(b) for the five days the owner has from written notice by an occupant who is not the owner or by an official with property inspection powers (state code, accessed 2026-08-23)
Core statewide statute for the dwelling. Re-read on 2026-08-23 through r.jina.ai because docs.legis.wisconsin.gov refuses connections from here, and the (3)(b) wording confirmed a second time by exact-phrase search. The five days run from the occupant's own written notice, not only from an inspector's.
Wisconsin Statutes section 101.149 , 101.149(1)(b) for the residential building definition, (2) for the triggers and locations, (3)(am) for five days from a certified inspector's notice, (3)(b) for five days from the occupant's own written notice to repair or replace, (4) tampering, (5) the sealed combustion exemption, (8) penalties (state code, accessed 2026-08-23)
Statutory framework for the residential building, which Wis. Stat. 101.01(12) makes reach any structure used by the public "or by 3 or more tenants", so a three-unit rental is inside this section as well as inside 101.647. Read on 2026-08-23 through r.jina.ai, with (3)(b) and (8)(a) each confirmed by a second route. (8)(a) orders correction "within 5 days or within such shorter period as the respective department determines is necessary", then forfeits $50 for each further day.
Wisconsin DSPS code archive Comm 28 and SPS 328 smoke and carbon monoxide detectors , Comm 28.04 and SPS 328 references (building code, accessed 2026-02-17)
Administrative-code implementation details including placement and owner-occupant duties.
Wisconsin DHS carbon monoxide poisoning publication , Placement and public guidance references tied to SPS 328.04 (agency guidance, accessed 2026-02-17)
Public-facing guidance aligned to administrative-code placement expectations.
Wisconsin DSPS carbon monoxide detectors overview , Overview references to statutes and code pathways (agency guidance, accessed 2026-02-17)
Supplemental DSPS framework summary for occupancy-specific implementation.

Disclaimer: This page explains the law as it stood on August 24, 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 Wisconsin statutes create the CO detector duty?

Wisconsin sections 101.647 and 101.149 are the two to cite, with SPS 328 implementation detail providing practical placement and operations context. Teams should read statute and code together because obligations include both installation and ongoing functionality. Relying on one summary line can miss exemption and maintenance conditions that matter in enforcement review. Wisconsin compliance files should keep section citations, detector inventory, and maintenance logs in one property packet. Include local enforcement contact information in that packet.

In Wisconsin lodging settings, what placement map should be kept for each sleeping area?

Wisconsin code materials cited here use floor-level placement language that includes basement coverage and excludes certain spaces such as attic and storage-only areas in covered dwelling contexts. Guidance tied to SPS 328 also reinforces sleeping-area and level-based coverage planning. Operators should document each installed location and keep device records by unit. Wisconsin inspection outcomes are stronger when placement decisions and code references are stored together with dated photos or checklists.

How are owner and occupant maintenance duties handled in Wisconsin?

Cited Wisconsin materials assign installation and response duties to owners while requiring non-owner occupants to maintain detectors and provide written notice when devices are not functional. This split should be reflected in lease language, move-in forms, and work-order procedures. Managers should track notice date, response date, and correction completion in one workflow. Wisconsin files with clear duty allocation are easier to defend during disputes and code-inspection follow-up. Keep notice and correction receipts attached to each unit record.

What statewide fine table is listed for Wisconsin noncompliance?

The cited Wisconsin sections used here focus on requirements and anti-tampering obligations but do not present one stand-alone statewide fine table in the same text set. That does not eliminate risk, because unresolved deficiencies can still produce enforcement and liability exposure through local administration. Teams should treat correction timing as a core control and preserve proof of remediation. Wisconsin notices should cite the applicable statute and SPS section for each violation.

Are all-electric Wisconsin units always exempt?

Not always. Wisconsin exemptions are tied to statutory and code conditions, so operators should review attached-garage, fireplace, and fuel-source factors before classifying a unit as outside detector requirements. Exemption decisions should be written and stored with the governing section citation and local interpretation if needed. This prevents inconsistent turnover decisions across portfolios. Wisconsin compliance records should show who approved each exemption and when it was reviewed. Document exemption reevaluation dates after major occupancy changes.

How does Wisconsin compare with Minnesota compliance frameworks?

Wisconsin combines sections 101.647 and 101.149 with SPS implementation pathways, while Minnesota operators work from a different statutory and rule blend with its own enforcement profile. Regional teams should use separate Upper Midwest matrices rather than one shared template. For side-by-side planning, review Minnesota CO detector laws and compare trigger language, role allocation, and documentation controls. Wisconsin teams should keep statute references separate from Minnesota rule citations in shared SOPs.

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