California Smoke & Carbon Monoxide Detector Laws

The importance of smoke and carbon monoxide detectors in our homes is obvious-they could save our lives and the lives of those we love. As such, the state of California has obligatory smoke detector laws that all homeowners are required to implement.

It is mandatory in California for all single-family dwellings, including prefab homes, to have workable smoke detectors in designated areas, specifically in and/or near sleeping areas. The regulations surrounding installation, placement and the type of detectors vary but all detectors used must be approved and listed by the State Fire Marshal and installed in accordance to established procedures.

Battery Operated or Hardwired

All houses built prior to 1992 are allowed to have battery-operated smoke detectors. Home built after 1992 or those that have been upgraded or remodelled must have detectors that are hardwired and have a battery back up.

Remodelled or Repaired

If your home has been renovated, remodelled or had any additions or repairs since August 14, 1992 that required a permit and cost more than $1,000, smoke detectors are required in all bedrooms as well as in a central location (i.e. a hallway) outside the bedroom.

For additions or any new construction, smoke detectors must be hardwired into your electric system and have a battery backup.


Again, homes that predate 1992 can have a single, battery operated smoke detector in a hallway that is central to all bedrooms. If the home has bedrooms on multiple floors, or in different areas of the house, a smoke detector must be placed on each level or in each section of the home near the sleeping areas.

Dwellings built after 1992 need a detector in each bedroom as well as one centrally placed in a corridor. These need to be both hardwired and have battery backups.

Local Ordinances

There may be additional smoke detector requirements depending upon where you live. For the specific guidelines in your city, check with the local building and safety department.

Carbon Monoxide Detector Requirements

The Carbon Monoxide Poisoning Prevention Act of 2010 requires owners of all single-family homes with an attached garage or a fossil fuel source (a furnace, HAVC unit, fireplace, gas stove, etc.) to install carbon monoxide detectors within the home. Owners of multi-family leased or rental dwellings, such as apartment buildings, rented single family homes and duplexes are also obligated to install CO detectors.

CO detectors are not the same as smoke detectors, but there are devices that function as both, emitting different sounds depending upon whether it detects smoke or carbon monoxide.

At high levels, this invisible and odorless gas can have deadly effects within minutes. Carbon monoxide (CO) is manufactured when a fuel such as gas, oil, kerosene, wood or charcoal is burned. If your appliances that use fuel are properly used and maintained, the amount of CO they generate is minimal. But, when an appliance isn’t operating correctly or they are used improperly, dangerous levels of CO can result.

Where to Install CO Detectors

Install a CO alarm outside each sleeping area as well as one on every level of your house, including basements. These inexpensive detectors can be purchased at any home improvement store and can be hardwired, plugged into an electrical outlet or battery-operated. Additional information on carbon monoxide and CO alarms is available on the Cal Fire website.

Selling Your Home

If you sell your home, you will be required to ensure your house meets the mandatory requirements and will need to provide documentation to the buyer proving compliance with California’s smoke and carbon monoxide detector laws and regulations. Your Realtor can assist you in assessing whether your home conforms to the regulations and bringing it into compliance if it falls short.