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Carbon Monoxide Alarm Information Center


The 2009 Oregon Legislature passed HB 3450, the Lofgren and Zander Memorial Act, requiring the installation of carbon monoxide alarms in specific residential applications with a carbon monoxide source. The purpose of the bill is to reduce deaths and poisonings from carbon monoxide.
The Oregon Office of State Fire Marshal (OSFM) worked with partners and stakeholders to develop rules for minimum standards for carbon monoxide alarms in one- and two-family dwellings and multifamily housing. The OSFM continues to educate Oregonians about the carbon monoxide alarm requirements.
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Carbon Monoxide Alarm Frequently Asked Questions (FAQ)

An individual or entity should not rely on these FAQs to determine compliance with the statutes or rules. The questions and answers presented here do not constitute legal advice.


General Carbon Monoxide Alarm Information

Q. What is a carbon monoxide (CO) alarm?

A. A CO alarm detects CO and produces a distinctive audible alert when CO is detected. It may be a standalone unit or part of an alarm system. (OAR 837-047-0110)


Q. What types of carbon monoxide (CO) alarms are available?

A. CO alarm: Activated by CO, Smoke/CO alarm: Activated by smoke or CO, and Gas or Explosive Gas/CO alarm: Activated by CO, propane, or natural/methane gas. CO alarms must be battery operated or receive their primary power source from the building wiring with a battery back-up. Plug in devices must have a battery back-up. (OAR 837-047-0140)


Q. What is a carbon monoxide (CO) source?

A. A heater, fireplace, appliance (i.e., furnace, dryer, or water heater), or cooking source (i.e., stove, oven) that uses coal, kerosene, petroleum products, wood, or other fuels (i.e., oil or natural gas) that emit CO as a by-product of combustion; or an attached garage with an opening that communicates directly with a living space. (OAR 837-047-0110)


Q. Where do I install carbon monoxide (CO) alarms?*

A. Install CO alarms on each level of your home with bedrooms (sleeping areas).

  • A CO alarm must be located within each bedroom or within 15 feet outside of each bedroom door. Bedrooms on separate floors in a structure containing two or more stories require separate CO alarms. 
  • All CO alarms must be installed in accordance with the manufacturer's recommended instructions. (OAR 837-047-0130)

​​* Please note: this is required when selling or renting a home.


Q. Are carbon monoxide (CO) alarms required in bedrooms?

A. No, but it is recommended to install them in the bedrooms and within 15 feet outside of each bedroom door. The law requires a CO alarm in each bedroom or within 15 feet of each bedroom door; however, ductwork from sources often goes directly to bedrooms, bypassing hallways outside of them. (OAR 837-047-0130).


Q. May I replace a hard-wired smoke alarm with a carbon monoxide (CO) and smoke alarm?

A. Yes. You may replace a hardwired smoke alarm with a hardwired with battery back-up CO/smoke alarm

  • Switching from one manufacturer’s unit to another may require a power adapter plug.
  • Manufacturers advise adapter plugs may be changed using wire nuts and may require a licensed electrician.


Q. Are carbon monoxide (CO) alarms required on every level?

A. No. They are required on each level with bedrooms (sleeping areas). (OAR 837-047-030)


Q. How often do I replace my carbon monoxide (CO) alarm?

A. CO alarms should be replaced when the end-of-life signal is activated, the manufacturer’s replacement date is reached, or when they fail to respond to operability tests. (NFPA 720)


Q. How do I keep my carbon monoxide (CO) alarm working?

A. Test alarms monthly. CO alarms must be maintained, tested, and batteries replaced according to the manufacturer’s recommended instructions. (OAR 837-047-0150)


Q. What should I do when the carbon monoxide (CO) alarm sounds?

A. Get outside to fresh air and call 9-1-1 or your local emergency number for help. If anyone is experiencing symptoms of CO poisoning, get medical attention immediately.


Carbon Monoxide Alarm Information for Real Estate Agents, Home Sellers, and Home Buyers

Q. Are carbon monoxide (CO) alarms required when selling a home?

A. If a home has a CO source, CO alarms are required before it can be sold. Effective April 1, 2011, sellers of one- and two-family dwellings, manufactured dwellings, or multifamily housing containing a CO source must have one or more properly functioning CO alarms before conveying fee title or transferring possession of a dwelling. (OAR 837-047-0120)


Homes built during or after 2011 require a CO alarm regardless of the presence of a CO source.


Q. Are carbon monoxide alarms required in new home construction or remodels?

A. Yes. The CO alarm requirements for new construction, reconstruction, alteration, and repair are applicable regardless of the presence of a CO source. (Oregon Residential Specialty Code, Carbon Monoxide Alarms)


Q. Can I have battery-operated CO alarms in new construction?

A. Yes. Section R315.4.1 of the 2011 ORSC states “Single station CO alarms shall be battery operated, or may receive their primary power from the building wiring system.” If a homeowner chooses to install the electrical plug-in type, those CO alarms need to have a battery back-up feature.


Carbon Monoxide Alarm Information for Property Management, Landlords, and Tenants

Q. Are carbon monoxide (CO) alarms required in rental dwelling units?

A. If you have a CO source, CO alarms are required in rental dwelling units. Effective April 1, 2011, landlords must provide properly functioning CO alarms for one- and two-family dwelling or multifamily housing containing a CO source. The landlord shall provide a new tenant with alarm testing instructions. If a CO alarm is battery-operated or has a battery-operated backup system, the landlord shall supply working batteries for the alarm at the beginning of a new tenancy. (OAR 837-047-0120, 0160)


Q. What are my obligations as a tenant?

A. A tenant must test, at least once every six months, and replace batteries as needed in any CO alarm provided by the landlord and notify the landlord in writing of any operating deficiencies. (OAR 837-047-0160)

A tenant may not remove or tamper with a CO alarm. Tampering includes removal of working batteries. (OAR 837-047-0170)


Q. What do I do if I am renting and have a CO source, and my landlord has not provided a working CO alarm?

A. A tenant must notify the landlord in writing of any operating deficiencies. (837-047-0160)

If the landlord receives written notice from the tenant of a deficiency in a CO alarm, other than dead batteries, the landlord shall repair or replace the alarm. (ORS 90.317) ​​
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Oregon Carbon Monoxide Alarm Law Requirements When Selling or Renting a Home​

Smoke & Carbon Monoxide Alarm Safety Brochure

Building Codes Division
 - Carbon Monoxide Alarms Residential Construction

Consumer Products Safety Commission - 
Carbon Monoxide Information 

National Fire Protection Association - Carbon Monoxide Information 

Smoke and Carbon Monoxide Alarm Power Source and Hush Feature Requirements      Use this chart to provide clarification on the power source and hush feature requirements of smoke and CO alarms as it relates to Oregon law. The OSFM does not endorse any particular brand of smoke or CP Alarm.

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