Smoke and CO Alarm Check: California and Arizona

It's time to test your smoke and carbon monoxide (CO) alarms. Press the test button on each one every month and replace batteries as needed. In California, state law also requires CO alarms in many homes and working smoke alarms when a home is sold.

How do I test smoke and CO alarms?

Testing takes a few minutes. Walk through the house and check every alarm.

1. Tell everyone at home you're testing.
2. Press and hold the test button until the alarm sounds.
3. If it's quiet or weak, replace the battery and test again.
4. If it still fails, replace the alarm.
5. Check the manufacture date on the back. Replace smoke alarms 10 years after that date.

The U.S. Fire Administration says to test every alarm once a month. Replace 9-volt batteries at least once a year, including the backup battery in hardwired alarms. Long-life 10-year batteries are sealed and can't be replaced.

Where should alarms go?

• Smoke alarms: one on each floor, plus one in every bedroom and one in the hallway or area outside where people sleep (USFA). Place them up high, on the ceiling or near the top of a wall.
• CO alarms: near each sleeping area and on each floor of the home (CPSC).
• Interconnected alarms are worth it. Trigger one, and every alarm in the house goes off.

You can't see or smell CO. Warning signs include confusion, headache, nausea and dizziness. If a CO alarm sounds, get outside to fresh air, then call 911.

What does California require for CO alarms?

California's Carbon Monoxide Poisoning Prevention Act came from SB 183 in 2010.

Under Health and Safety Code §17926:

• Owners must install a CO device approved by the State Fire Marshal.
• The rule covers homes with a fossil-fuel heater or appliance, a fireplace or an attached garage.
• SB 183 counts wood and fuel gases, as well as coal, oil, kerosene and other petroleum products, as fossil fuels.
• Existing single-family homes had to comply by July 1, 2011. Other existing dwelling units had to comply by January 1, 2013.
• A violation is an infraction of up to $200, after a 30-day notice to correct.

Landlords must keep CO devices working in rentals under §17926.1.

What does California require for smoke alarms?

Health and Safety Code §13113.7 requires State Fire Marshal-approved smoke alarms in dwellings, installed per the maker's instructions. Rental owners must make sure alarms work at the start of each tenancy.

The 10-year sealed battery rule is in §13114. Since July 1, 2014, a battery-only smoke alarm approved for sale in California must have a sealed battery that lasts at least 10 years. Since January 1, 2015, new alarms must show a manufacture date, have a spot to write the install date, and include a hush button.

So when you replace a battery-only alarm, expect the new one to have a sealed 10-year battery.

What does California require when a home is sold?

Smoke and CO alarms come up in most California home sales.

• Smoke alarms: Under §13113.8, a single-family home must have an operable smoke alarm when sold. The seller must give the buyer a written statement that the home complies.
• CO devices: SB 183 added a CO device disclosure to the state's Real Estate Transfer Disclosure Statement. It also added a seller certification that the home will meet smoke detector and water heater rules at close of escrow.

Some transfers are exempt, so ask your agent whether yours is. Test and update alarms before listing so the disclosures are simple.

What about Arizona?

Arizona rules for alarms in existing homes come mainly from the building codes each city or county adopts. Kingman, for example, adopts the 2018 International Residential Code, with Appendix J for existing buildings.

We could not confirm a statewide Arizona rule like California's sale requirement. Call your city or county building department to ask what applies to your home.

Is the clock change a good reminder?

Daylight saving time ended November 1, 2026, per NIST. If you changed your clocks, test your alarms this week too.

Arizona doesn't observe daylight saving time, except on the Navajo Nation. Arizona homeowners can pick a set day instead, like the first of each month.

How Pleasant Hill can help

Getting ready to sell in California or Arizona? Contact us, or reach Nancy Navarro in Hesperia or Lana Stephens in Kingman.

General information, not legal, tax or lending advice. Rules, fees and rates change; confirm with the agency linked above or ask us. Pleasant Hill Real Estate Group · CA DRE Corp. #01997374 · AZ Entity Lic. #LC694532000 · Equal Housing Opportunity.