Smoke and CO Alarm Requirements in Oregon and Washington: A 2026 Homeowner's Guide

Oregon rules (Portland, Gresham, Beaverton and the rest of the state)

Smoke and CO alarm rules are triggered by events: a sale, a rental, a building permit, new construction. That is why two identical houses on the same street can have different legal requirements. Start with your situation.

Washington runs on a different logic: it keys smoke alarms to the year the home was built and whether it has been sold, and it exempts older owner-occupied homes from CO rules until they change hands.

Washington rules (Vancouver, Camas, Battle Ground and the rest of the state)

Washington's smoke alarm law is RCW 43.44.110. It covers dwellings occupied by someone other than the owner, homes built after December 31, 1980, and any home sold on or after July 1, 2019. Homes built in Washington after 1980 must have alarms powered by the building wiring (WAC 212-10-025). CO alarms come from RCW 19.27.530 and the state residential code.

Where smoke and CO alarms go

Placement rules are close in both states, with two differences that trip people up: how far the hallway alarm can be from the bedrooms, and where CO alarms go. For existing Oregon homes, the fire marshal's rule (OAR 837-045-0050) also says that when bedrooms are upstairs, the alarm goes as close as practical to the center of the ceiling directly over the stairway.

The 10-year rule, and why CO alarms don't last as long

NFPA 72, the national alarm standard, says smoke alarms in one- and two-family homes shall not remain in service longer than 10 years from the date of manufacture. The Oregon State Fire Marshal repeats the same 10-year rule for homes being sold or rented. The date that counts is the one printed on the back of the alarm, not the day you installed it. An alarm that sat in a warehouse for two years has eight years left.

A working Test button doesn't prove an old alarm is still sensitive. Sensors degrade with age, which is exactly why the replacement date exists.

CO alarms have shorter and less uniform lives because the sensor itself wears out. Kidde rates CO alarms made in 2013 or later for 10 years (with a few model exceptions) and older ones for 7. First Alert says most of its CO alarms last 5 to 7 years. CDC's advice is to follow the manufacturer, or replace every 5 years if you don't know. Kidde notes that its CO alarms can't detect CO once they enter end-of-life mode.

Take one alarm down and look at the label. If it's older than 10 years, or has no date at all, assume the rest of the set is the same age. Replace them together. You'll see why that matters for hardwired systems below.

How to read the date

Twist the alarm off its base (hardwired alarms unplug from a short wiring harness). The label on the back shows a manufacture date, sometimes a "replace by" date, and the model number. Newer alarms may also chirp to tell you they've reached end of life. Take a photo of the label before you put it back: the model number is what an electrician needs to match a replacement.

Why a hardwired smoke alarm chirps, and what the chirp means

Hardwired alarms run on house power with a battery backup, so a chirp doesn't always mean a dead battery. The pattern tells you what's wrong, and the patterns differ by brand. These are the signals from the manufacturers' own guides.

• End of life. A common cause in older homes. A new battery won't stop it: Kidde states this directly for its CO alarms.
• Battery drawer not fully closed, or the battery is loose or the wrong type.
• Dust, insects or humidity in the sensing chamber. Bathrooms and dusty remodels are frequent culprits.
• A power surge or loose connection on the hardwired circuit. First Alert lists this as a cause of chirps on hardwired units.
• The wrong alarm. On an interconnected system, the chirp comes from one unit, but an alarm sounds on all of them. On Kidde alarms, the unit that started the alarm flashes its light about once a second while sounding.

Replacing hardwired alarms: brands, wiring and permits

Hardwired stays hardwired. The Oregon State Fire Marshal says that if hardwired alarms were installed when the home was built, they must be replaced with hardwired alarms. In Washington, homes built after 1980 must have alarms powered by the house wiring (WAC 212-10-025). In either state, swapping a hardwired alarm for a battery unit and capping the wires is not a legal fix.

Brands don't mix. Interconnected alarms talk to each other over a third wire. Kidde says its alarms are listed only with the compatible models named in each user guide. Mixing makers creates a system that hasn't been tested as a whole, and it can cause nuisance alarms or failure to alarm. Adapter plugs exist, such as Kidde's KA-B3 and First Alert's ADK-12, but they are model-specific. In practice, the clean answer is to replace the whole interconnected set with one compatible family. That also resets every alarm's 10-year clock at once.

Know the limits. Kidde's installation guide cites the NFPA interconnect limit: no more than 12 smoke alarms, and no more than 18 alarms in total, on one interconnected system. Standard wiring is black (hot), white (neutral) and red (interconnect), but harness colors vary by maker. Manufacturers recommend a qualified electrician for the wiring. Always turn off the breaker first, and don't assume a harness is dead because the alarm came off.

When we replace alarms in Oregon, the permit or minor label is part of the job and shows on the quote. In older homes with no hardwired alarms at all, fishing new cable to every bedroom can mean opening ceilings. Sealed 10-year battery alarms with listed wireless interconnect are often the practical choice there: in Oregon, alterations may use battery power, and under the current (2023) code interconnection isn't required where finishes aren't removed. The 2026 code expected October 1 would remove that exception. For a sale, a rental or new construction, check the requirement first.

What alarm work costs

Our starting prices for Portland and Vancouver are below. You get a written quote before any work starts; it names the alarm models and includes any permit the job needs.

Photoelectric, ionization or dual-sensor? What changed with UL 217

Smoke alarms sold in the U.S. are listed to UL 217. The 8th edition applies to alarms tested from June 30, 2024. It added two fire tests using burning and smoldering polyurethane foam, the material in most modern furniture, and a cooking nuisance test. That last one matters because nuisance alarms from cooking are one of the most common reasons people disconnect alarms. Alarms listed to the new edition are designed to be less prone to cooking false alarms.

The new standard does not require you to replace alarms that are already installed. We found no Oregon or Washington rule that does either. But if your alarms are near the end of their 10 years anyway, their replacements will be built to the newer test. Check that the package says it meets the current UL 217, often described as resistant to cooking nuisance alarms.

On sensor type, the U.S. Fire Administration recommends having both ionization and photoelectric alarms, or dual-sensor alarms, and choosing interconnected alarms. Near kitchens, photoelectric alarms are the better fit, and Oregon's code lets them sit closer to the range (6 feet, versus 20 for ionization). In Oregon, ionization alarms must have a hush button, and battery-only ionization alarms must come with a 10-year battery (ORS 479.297).

Carbon monoxide: why the alarm matters in a Northwest winter

Carbon monoxide has no smell and no color, and early symptoms feel like the flu: headache, dizziness, nausea, fatigue. According to the CDC, unintentional CO poisoning not linked to fires kills more than 400 Americans a year and sends more than 100,000 to the emergency department. In Washington, the Department of Health counts more than 10 deaths a year. In Oregon, the Health Authority reported 121 emergency and urgent care visits for CO poisoning in 2024.

The usual sources in our area are gas furnaces and water heaters, fireplaces and wood stoves, cars idling in an attached garage, and generators run too close to the house during outages. If you're adding backup power, our generator vs. battery backup guide covers placement.

A CO alarm is designed to sound before levels become dangerous for a healthy adult, not at the first trace. UL 2034, the CO alarm standard, sets time windows that get shorter as the concentration rises.

Whatever the level, a CO alarm in its emergency pattern means the same thing: don't hunt for the cause. Get everyone outside, including pets, and call 911 from outside. Don't go back in until the fire department says it's clear.

Landlords and tenants: who does what

Both states split the work between the owner and the tenant, but they split it differently.

Selling a home: the alarm checklist before you list

Alarm requirements at sale are cheap to satisfy and awkward to fix in the middle of escrow. Walk the house with this list before the listing photos.

1. Check every date. Anything older than 10 years, or undated, comes out.
2. Cover every bedroom, the hall outside the bedrooms and every level. In Oregon, keep the hallway alarm within 21 ft of every bedroom door. Washington's legal minimum at sale is one alarm, but full coverage is the safer standard.
3. Hardwired stays hardwired, with one compatible brand on the interconnect.
4. Oregon ionization alarms need a hush button, and battery-only ionization alarms must come with a 10-year battery.
5. Add CO alarms if the home has a gas appliance, fireplace, wood stove or attached garage. In Oregon, put one in each bedroom or within 15 ft of its door, with a separate alarm on each floor with bedrooms. Washington requires CO alarms at every sale.
6. Test everything once installed, and leave the manuals for the buyer.

In Washington, alarm repairs made only because of the sale don't require adding interconnection where there was none. In Oregon, a buyer who closes without the required CO alarms can sue for actual damages or $250 per unit, whichever is greater, within a year.

Free smoke alarm help in Portland, Vancouver and Clark County

Local fire agencies and the Red Cross will help with battery alarms, especially for seniors, people with disabilities and families who can't afford them. Don't count on them for hardwired alarms: Vancouver Fire says it cannot assist with hard-wired alarms, and Portland Fire & Rescue says hardwired alarms must be installed by a qualified electrician.

Rules that change soon

Oregon expects to adopt the 2026 Oregon Residential Specialty Code, based on the 2024 International Residential Code, around October 1, 2026. The proposed changes renumber the alarm sections and would remove Oregon's exception that skips interconnection in existing areas when finishes aren't removed. They would also add smoke alarms for sleeping lofts. Washington's 2024 codes take effect May 3, 2027.

Code updates mostly affect new construction and permitted work. They don't reach back into a home nobody is working on. If you're planning a remodel, an ADU or a basement bedroom, ask which code edition your permit falls under.

When to call an electrician

Battery alarms are an easy DIY job. Call us for these:

• Hardwired alarms that are 10 or more years old, or have no date.
• A hardwired alarm that keeps chirping after a new battery, or a set that goes off with no smoke.
• Mixed brands on the interconnect after years of one-off replacements.
• No alarms upstairs, in the basement or in a converted bedroom, and you want them interconnected.
• Getting a home ready to sell or rent, where hardwired alarms must stay hardwired.
• Adding a bedroom, an ADU or a basement suite, where the permit will trigger new alarm rules.

Fire Prevention Week runs October 4–10, 2026. It's a good week to press the Test button on every alarm and read the dates on the back. And if you run space heaters in winter, read our guide on why a space heater trips the breaker: the fatal Portland fire in January involved both a heater on an extension cord and no working alarms. For alarm replacements and new wiring, see our residential electrical services or book the free safety check.

Sources

• Oregon statutes: ORS 479.255, 479.260, 479.270, 479.280, 90.316, 90.325, 105.838, 105.840.
• Oregon rules: OAR 837-045-0050, 837-045-0060, 837-047-0130, 918-309-0220.
• Oregon State Fire Marshal, Smoke Alarm Laws for Selling or Renting; Portland Permitting & Development, Smoke and carbon monoxide alarm requirements; Portland City Code 29.30.240 and 29.30.245.
• Oregon Building Codes Division, 2026 ORSC adoption.
• Washington: RCW 43.44.110, RCW 59.18.060, WAC 212-10, WAC 51-51-0314, WAC 51-51-0315, WAC 296-46B-901; State Building Code Council.
• UL, new smoke alarm requirements (UL 217, 8th edition); U.S. Fire Administration, Smoke alarms.
• Kidde, CO alarm replacement and interconnecting with other brands; First Alert, what the beep means.
• CDC, Carbon monoxide poisoning basics; Washington DOH, CO poisoning report to the Legislature; Oregon Health Authority, winter CO warning (December 2025).
• NFPA smoke alarm data release, September 2024; Portland Fire & Rescue, smoke alarms; City of Vancouver, smoke and CO alarms.