Does Pennsylvania Require CO Detectors? Act 121 and Rental Rules

Last verified: February 16, 2026

Pennsylvania carbon monoxide detector laws are shaped by Act 121 of 2013, which is narrower than a full statewide home mandate. The strongest statewide installation language focuses on covered multifamily rental settings and specific risk conditions such as fuel-burning equipment or attached garages.

The act also preserves municipal authority to adopt equal or more demanding requirements, so local code overlays remain important. Owners should map which units are covered, maintain operable devices near sleeping areas, and document tenant notice and repair workflows.

This targeted framework means compliance decisions in Pennsylvania are highly occupancy-specific rather than one broad rule for every home.

Quick Safety Summary

CO detector requirements for Pennsylvania
Applies to homes?	No
Applies to rentals?	Yes
Applies to hotels/STRs?	No

When Are CO Alarms Required?

Buildings with fuel-burning appliances
Buildings with attached garages
Home sales or property transfers
Applies to apartments in multifamily dwellings that use a fossil-fuel-burning heater or appliance, a fireplace, or an attached garage.
Multifamily requirement had a compliance deadline: within 18 months of the act’s effective date (Act date: 2013-12-18).

Where to Install CO Alarms

Operational, centrally located approved CO alarm installed in the vicinity of the bedrooms and the fossil-fuel-burning heater or fireplace (for covered multifamily apartments).

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

Device Requirements

Approved CO alarm: UL 2034 (CO alarm) or UL 2075 (CO detector) (as applicable).
Combination smoke/CO devices permitted if CO side meets UL 2034 or UL 2075 and smoke side meets UL 217 (smoke alarm) or UL 268 (system smoke detector), and the alarm differentiates smoke vs CO.
CO detection systems permitted if installed/maintained per NFPA 72 and NFPA 720 and compliant with UL 2075.
“Installed” includes hardwired, plug-in (no switch other than breaker), or battery units attached to wall/ceiling in accordance with NFPA 720.

Landlord and Tenant Responsibilities

Landlord: For covered multifamily rentals: provide and install an operational, centrally located approved CO alarm near bedrooms and the fossil-fuel heater/fireplace; replace missing/inoperable units from prior occupancy; ensure batteries are operating at move-in.

Tenant: For covered multifamily rentals: keep device in good repair; test; replace batteries as needed; replace devices rendered inoperable during occupancy; notify owner/agent in writing of deficiencies.

Owner generally not responsible for maintenance/repair/battery replacement during occupancy (except the move-in duties above); responsibility reverts to owner upon vacancy.

Enforcement

Enforced by: Not specified in Act 121; the act creates a summary offense for willful noncompliance. Municipalities may adopt equal or more stringent requirements.

Enforcement typically occurs:

Enforced when willful failure to install or maintain required alarms is cited/charged.

Section 7 explicitly preserves municipal authority to adopt stricter CO-alarm requirements.

Penalties for Non-Compliance

Willful failure to install or maintain required approved CO alarms is a summary offense punishable by a fine of up to $50.

Act 121 (2013), Section 6

Additional Notes

Act 121's statewide installation mandate in this text is explicit for covered multifamily apartments; for one- and two-family homes, this act mainly adds a sale-transfer disclosure requirement (Section 4(a)).
Act 121's statewide installation mandate is for covered multifamily apartments. For owner-occupied single-family homes, Act 121 mainly adds a sale-transfer disclosure requirement (Section 4(a)). Hotels are NOT covered under Act 121; PA Uniform Construction Code may require CO detection in new hotel construction.

Official Sources & References

Pennsylvania Carbon Monoxide Alarm Standards Act (Act 121 of 2013) — Enactment PDF — Sections 2, 4, 5, 6, 7 (state code, accessed 2026-02-16)
Primary statute defining approved alarms, multifamily requirements, owner/occupant duties, and penalties.
Pennsylvania Act 121 of 2013 — Carbon Monoxide Alarm Standards Act — Sections 2–6 (definitions, alarm requirements, responsibilities, enforcement, penalties) (state code, accessed 2026-02-17)
Full text of Act 121 (unconsolidated); CO alarm requirements for residential buildings, multifamily dwellings, and rentals; §50 fine for willful noncompliance
NCSL - Carbon Monoxide Detector Installation Statutes (Pennsylvania row) — Pennsylvania (secondary index, accessed 2026-02-17)
Cross-state summary of Act 121 scope and local-code overlay considerations.

Disclaimer: This information is provided for general guidance and is not legal advice. Requirements may vary by city, county, and building type. Always verify current rules with local authorities and official sources.

Frequently Asked Questions

Does Act 121 require CO alarms in every Pennsylvania home?

No. Act 121 is not a blanket statewide requirement for every private home. Its clearest statewide installation duties focus on covered multifamily contexts and risk-based scenarios that involve fossil-fuel equipment, fireplaces, or attached garages. Pennsylvania owners should review occupancy type and project context before assuming a unit is out of scope. For many properties, local building or fire code adoption can add requirements beyond Act 121. This is why compliance planning in Pennsylvania starts with scope classification, then applies local overlays and property-level conditions.

Where should alarms be placed in covered Pennsylvania rental units?

Act 121 requires an operational, centrally located approved carbon monoxide alarm near bedrooms and relevant fuel-burning equipment in covered multifamily settings. Device type should follow listed standards such as UL 2034 or UL 2075 as applicable. Owners should verify that placement supports both code language and practical audibility for sleeping occupants. During turnovers, teams should retest devices and document condition because maintenance responsibility may shift with occupancy status. Placement errors are a common compliance gap, so written inspection checklists are recommended for each unit.

What penalty applies for willful noncompliance in Pennsylvania?

Act 121 Section 6 treats willful failure to install or maintain required alarms as a summary offense with a fine that can reach 50 dollars. While the fine amount is modest, repeated noncompliance can still create legal and liability exposure, especially after an incident. Operators should not treat the penalty as the only risk factor. Documentation of installation, tenant communication, and repair response is often more important in litigation than the citation amount itself. Municipal code provisions can also increase operational consequences beyond the baseline statute.

How should landlords and tenants split responsibilities in Pennsylvania?

Act 121 sets move-in and replacement expectations for owners in covered rentals, while tenants are expected to maintain and report device issues during occupancy. The exact duty split can depend on whether the issue occurred before occupancy, during tenancy, or after vacancy turnover. Because disputes often center on notice and response timing, landlords should keep written logs of tenant notices, service calls, and final operability checks. Lease language should mirror the statutory framework and local code additions so responsibility is clear before incidents occur.

Can Pennsylvania municipalities impose stronger CO requirements?

Yes. Act 121 expressly preserves local authority to adopt equal or more demanding carbon monoxide alarm rules. This means a city or borough can require broader coverage than the statewide baseline in certain occupancies. Owners operating across multiple Pennsylvania jurisdictions should maintain a municipal matrix that tracks local amendments and inspection expectations. Relying only on state text can leave gaps, especially for renovation projects and mixed-use properties where local code officials apply additional standards.

How do Pennsylvania duties compare with Ohio fire-code coverage?

Pennsylvania Act 121 is targeted and occupancy-specific, while Ohio uses a broader fire-code framework with detailed coverage in Section 915 and existing-building language in Section 1103.9. Multi-state managers should avoid merging these into one policy because enforcement pathways differ. Pennsylvania often starts with Act 121 scope analysis, while Ohio workflows begin with occupancy classification under the fire code. For the Ohio model and citation structure, review Ohio CO detector laws before standardizing regional procedures.

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