NHI Technical Bulletin: WA and OR Laws/Rules Regarding Smoke Detectors and Carbon Monoxide Detectors

This article explains what the Oregon and Washington home inspector Standards of Practice have to say (or not say) about smoke detectors and carbon monoxide detectors, highlights what some of the requirements are about each for real estate transactions (which have nothing to do with inspectors), and how Nickelsen Home Inspections, LLC handles smoke/CO detectors and alarms. At the end, we include links that may be important to you. By reading this material and checking the links, you will know what is included and not included in the inspection process and what is required during real estate transactions. 


Oregon’s Standards of Practice (SOP) governing home inspectors require the inspector to “report on” what they refer to as “smoke alarms”, and the “Oregon certified home inspector shall report… the presence or absence of smoke alarms, and operate their test function, if accessible, except when detectors are part of a central security system.”

Regarding CO detectors, the SOP’s state that “the Oregon certified home inspector is not required to... observe… carbon monoxide detectors.UPDATE: The Oregon Standards of Practice were updated since this article was originally written. Oregon now requires home inspectors to "observe" the "operation" of "carbon monoxide detectors", and says nothing about noting whether they are installed in approved locations.


Washington’s SOP do not mention carbon monoxide detectors at all, and the only place where smoke detectors are mentioned (WAC 308-408C-110) it states that “the inspector is not required to inspect ancillary systems including but not limited to smoke/heat detectors”.

Q. “What about other laws? I’ve heard that these are required during real estate transactions.”

Answer: There are indeed “other laws” that are part of real estate transactions, and such laws have nothing to do with home inspectors. The home inspector may, as a courtesy and without setting a level of expectation, express or implied, mention things outside of their SOP’s, but are not required to do so. Agents and clients hiring inspectors are hiring them to perform inspections that are in accord with the regulations governing them as inspectors, and nothing more. It is critical that clients know what they are paying for, which is why they should carefully review the Standards of Practice prior to hiring an inspector. We supply these Standards prior to every one of our inspections, and anyone is free to contact our offices to obtain a copy at any time.

The Oregon Association of Realtors notes:

“In Oregon, no person may sell a dwelling without an approved smoke detector or smoke alarm installed... Because of this state law requirement, most residential real estate sale forms contain a representation by the seller that, at the earlier of possession or closing date, the dwelling will have operating smoke alarm(s)/detector(s) as required by law… The smoke alarm power source requirement is based on what was required at the time of construction or remodel. The power supply of a smoke alarm shall be a commercial power source, an integral battery or batteries, or combination of both. Solely battery-powered ionization smoke alarms must have a 10-year battery and a “hush” mechanism which allows a person to temporarily disengage the alarm. Photoelectric, dual-sensing ionization/photoelectric, combination smoke/carbon monoxide, and hardwired alarms do not require a 10-year battery or a hush feature. Ten-year batteries should not be placed in smoke alarms unless they are recommended by the manufacturer. According to the National Fire Protection Association… “Unless otherwise recommended by the manufacturer’s published instructions, single and multiple station smoke alarms installed in one- and two-family dwellings shall be replaced when they fail to respond to operability test, but shall not remain in service longer than 10 years from the date of manufacture.” All dwellings must have the proper type, number and placement of alarms as required by the building codes at the time the dwelling was constructed but not less than one alarm adjacent to each sleeping area and at least one alarm on each level of the dwelling. (Additional rules apply to rented property.) … [In Oregon], [a]ny person transferring a one or two-family dwelling or multifamily housing (additional rules apply to rental property) that contains a carbon monoxide source… must have carbon monoxide detectors/alarms installed… Homes with an attached garage with a door, ductwork, or ventilation shaft that communicates directly with a living space, must provide a properly functioning carbon monoxide alarm(s) installed at the location(s) that provide carbon monoxide detection for all sleeping areas of the dwelling or housing (on all levels of the home where there are bedrooms). For homes built during or after 2011, or that undergo a remodel or alteration that requires a building permit, CO alarms are required regardless of the presence of a CO source… Because of this state law requirement, most residential real estate forms will contain a representation that, at the earlier of possession or closing date, the dwelling will have an operating carbon monoxide detector as required by law. Sellers should anticipate the carbon monoxide alarm requirement as it is also included on the new seller’s property disclosure form.”

As the Washington State Department of Health states:

Washington State law (RCW 19.27.530) requires carbon monoxide alarms to be installed in new residences. As of January 1, 2013, carbon monoxide alarms are required in existing apartments, condominiums, … and single-family residences, with some exceptions. Owner-occupied single-family residences, legally occupied before July 26, 2009, are not required to have carbon monoxide alarms until they are sold. For more information on the carbon monoxide alarm requirements, contact your local building code official or see the State Building Code Council's Carbon Monoxide Alarm page.

Another source notes:

If you are getting ready to sell a home in Washington state, you probably need to go out and buy some carbon monoxide detectors to comply with a new state law. Washington began requiring carbon monoxide alarms for new construction on January 1, 2011, but now requires it for anyone looking to sell a home.

The Washington law (RCW 19.27.530) went into effect on April 1, 2012 requires the seller of any owner-occupied single-family residence to equip the home with CO alarms before a buyer may legally occupy the residence following the sale.

There are requirements regarding the presence of smoke detectors in homes during real estate transactions (https://apps.leg.wa.gov/rcw/default.aspx?cite=43.44.110), but there are no laws requiring the enforcement of that by home inspectors.


Oregon and Washington home inspector Standards of Practice have limited requirements for the home inspector regarding carbon monoxide detectors. However, there are requirements in each state that properties be equipped with them at the time of sale.

Oregon and Washington have limited requirements for home inspectors regarding smoke detectors. Washington specifically states that home inspectors are not required to inspect them or test them, whereas Oregon has some basic requirements about observing their presence or absence and testing them if accessible.


Given that we work in both Oregon and Washington, we prefer to do our inspections the same way. As such, if “accessible” we will test smoke detectors and note their presence or absence in a home. For us “accessible” means that we can reach the smoke detector from ground level and test it using our finger, unaided. If a tool, extension, stool, ladder, or anything else is required to test them, then the smoke detector is considered not “accessible”. In both Oregon and Washington, we will note on their presence or absence in the home, and we will note if there appears to be enough of them in the places that would typically be required by the manufacturer. However, being that home inspectors are not code or regulation enforcement officials, we do not get technical on the matter. Finally, inspectors are not required to dismount the smoke detector to check for age or whether they are hardwired together. If the smoke detectors appear to be over 10 years old, we will typically advise that any smoke detectors over 10 years old be updated and it will be up to those within the transaction to check for age and update them accordingly.

Regarding CO detectors: If we see them and they are "accessible" in the same manner as smoke detectors, we will test them. As there are no requirements for us to check for compliance in terms of location, we may not note of location compliance and if we do it should be received as a courtesy, not establishing a level of expectation, express or implied. Our blanket recommendation is that they be installed per manufacturer specifications and in areas specified by the manufacturer. We do not check compliance for real estate laws regarding CO detectors or enforce them. We expect what the States of Oregon and Washington expect: that the other people involved in the transaction can check themselves as to whether the CO detectors are installed in appropriate locations. 

Q. “How will I know whether or not the smoke detectors in the home are less than 10 years old if you don’t check?”

Answer: By checking yourself or having the selling party check. If there is no date on the back/top or side of the smoke detector or anywhere else on it, our recommendation is that you assume they are 10 years old or more and update them accordingly.

If you suspect (or if we suspect) that they are 10 years old or more and the selling party challenges this, then they could simply take a picture of the date stamp on every smoke detector in the home proving that they are less than 10 years old.

Q. “How will I know whether or not the number and placement of smoke detectors and CO detectors in the home is sufficient to meet requirements?”

Answer: Since we are not required to, we do not check to enforce the standards by the States of Oregon or Washington and, instead, defer to manufacturer specifications. To answer the question, then, you would read the instructions that come with the product. As noted above, we are only required (in Oregon) to "observe" the "operation" of them, not determine whether they are in approved locations that meet Code or any other requirements.

Q. “If you don't check for location compliance of CO detectors, how will I know whether they are installed in the right locations?”

Answer: When you are in the home you can certainly look for them yourself or, if you have a real estate agent, you might ask them to. You could also request that the seller confirm whether they are installed in the proper locations. With everyone having smart phones these days, it would be simple for the seller to snap a few pictures to get such confirmation. If you want to know about location compliance, you could obtain the make and model of the CO detectors and ensure that they are in the locations advised by the manufacturer.


The following links may give further information about Oregon and Washington home inspector Standards of Practice, CO and smoke detector regulations in each state for real estate transactions, and related matters. Between what was said above in this article and by reviewing the links, you should have more than enough information regarding the matter.


Nickelsen Home Inspections, LLC, originating out of Inspection Consulting, INC, which was established in the 1990's, is one of the most tenured and experienced inspection firms in Washington or Oregon, and is proud to be a family-owned operation. Performing inspections from the coast (Astoria, Newport, Lincoln, Long Beach, and more) to the valley (Portland, Salem, Olympia, Seattle), to the mountains (Hood River), and the high desert (Wenatchee, Bend, Yakima), and up through the Olympics (Bremerton, Port Angeles, Port Townsend and more), NHI is willing to travel far and wide for our clients and have been doing so for over two decades because they have asked! Nickelsen Home Inspections performs residential and commercial property inspections, as well as radon testing, sewer scopes, moisture intrusion inspections, construction draw, termite inspections, infrared thermal imaging, pest and dry rot inspections, NPMA-33 inspections, WDO inspections and more. If you are looking for experienced home inspectors, performing over 1,000 inspections a year, from a family-owned firm, you have come to the right place.

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