What are California's smoke and carbon monoxide alarm requirements, including the 10-year sealed battery rule?

Every California home must have working smoke alarms, and any home with gas appliances, a fireplace or an attached garage must also have carbon monoxide (CO) alarms. The rules sit in the state Health and Safety Code, with placement set by the California Residential Code and products approved by the State Fire Marshal. We read the code sections and a city building handout on November 3, 2026. This is general information, not legal advice; your city or fire department can add stricter local rules. Renters with other repair issues can also see storm prep for renters.

What is California's 10-year smoke alarm battery law?

Since July 1, 2014, every battery-only smoke alarm sold or offered for sale in California must have a nonreplaceable, nonremovable battery that can power it for at least 10 years (Health and Safety Code 13114). That means a new battery-only alarm has no battery to change: when it reaches the end of its life, you replace the whole alarm. Since Jan. 1, 2015, alarms must also show their manufacture date, have a space to write the install date, and have a hush feature. The rule is about what stores can sell. It doesn't force you to rip out an older battery alarm that still works: the law says a battery alarm that met the standards when it was installed still counts. The State Fire Marshal can exempt alarms tied to a fire alarm panel or low-power wireless systems, and hardwired alarms with a backup battery aren't battery-only.

Where do smoke and CO alarms have to go in a California home?

Smoke alarms go in every bedroom, outside each sleeping area and on every level; CO alarms go outside each sleeping area and on every level. These are the California Residential Code placements (sections R314 and R315) that apply to new homes and to existing homes when they get permitted work, as summarized in a City of Roseville building handout on the 2022 code. San Diego County homes follow the same state code. Permitted work triggers a check: for alterations, repairs or additions over $1,000 permitted since Jan. 1, 2014, the inspector can't sign off until you show the required smoke alarms are State Fire Marshal-listed (Health and Safety Code 13113.7), and homes with an attached garage or fuel-burning appliances need CO alarms added when permitted work is done.

What do landlords and tenants have to do about smoke and CO alarms?

What does the law require when a home changes owners?

A single-family home must have an operable, State Fire Marshal-listed smoke alarm when title transfers, and the outgoing owner must give the new owner a written statement saying so (Health and Safety Code 13113.8, in effect since 1986). The CO rule (17926) applies to every owner of a qualifying home at all times, not just at a transfer. In both cases the law says a missing alarm doesn't invalidate the transfer; the new owner's only remedy is actual damages up to $100. Court-ordered, foreclosure, estate and family transfers are exempt from the smoke alarm statement. If you just moved in, the 10-minute check below is the practical step.