How many carbon monoxide detectors are required in california

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This post was contributed by a community member. The views expressed here are the author's own.

In case you were not aware, as of January 1, 2013, if you live in multi-housing you need to be aware of the new state law requiring the installation of a Carbon Monoxide (CO) alarm.  Single family homes and multi family homes, not exceeding 4 units were subject to this law effective July 1, 2011. This California law requires the installation of a carbon monoxide (CO) alarm or a combined CO/Smoke detector.  


Carbon Monoxide (CO), also known as the “Silent Killer”, is the leading cause of accidental poisoning deaths in the United States, with over 500 per year and sends another 20,000 annually to emergency rooms nationwide.  Carbon Monoxide is an odorless, colorless and tasteless gas produced whenever any fuel is burned.  It can enter the home from sources such as a gas or wood-stove, fireplace, household appliances, vehicles and other devices that burn fuel.
According to the law, detectors must be installed in all dwelling units that contain fossil fuel burning heaters and appliances, as well as a fireplace.  It also applies to dwellings that have an attached garage.  The definition of fossil fuel is “Fuel derived from prehistoric organisms: any carbon-containing fuel derived from the decomposed remains of prehistoric plants and animals, e.g., coal, peat, petroleum natural gas, gasoline and firewood.”


Effective Dates for CO Alarm Installation:

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July 1, 2011 - all existing single-family dwelling units intended for human occupancy.
January 1, 2013 - all other existing dwelling units intended for human occupancy, e.g. condominiums, apartments and hotels. Approved CO Alarms:
New Construction must be hardwired with battery backup and interconnected.
Existing homes may be battery operated, plug-in with battery backup or hardwired with battery backup.


Installation Location:

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Carbon Monoxide alarms must be installed outside each separate sleeping area in the immediate vicinity of the bedroom(s), and on every level of home, including basements.

Fines: According to California law, if you do not comply with the new law, you may face a maximum $200.00 fine.  However, residents will receive a 30-day notice to correct, before fine will be imposed.


For further information, please click here.


If you are interested in getting Carbon Monoxide alarms installed in your home, apartment or condo, please give Steve’s Handyman Service a call.

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How many carbon monoxide detectors are required in california

Where to Install Carbon Monoxide Alarms

Where to Install Carbon Monoxide Alarms

Most people know that carbon monoxide alarms are important and save lives, but many are confused about where they should be installed. It can be tricky, since the manufacturer’s recommendations, state, and local requirements often don’t agree. The advice given here is based upon the California Residential Code (CRC).

Required Locations
Since 2011, the State of California has required carbon monoxide alarms in all homes and dwelling units (with gas fired appliances or attached garages). Section R315 of the CRC requires carbon monoxide alarms:

  1. Outside of each separate sleeping area in the immediate vicinity of the bedrooms.
  2. On every occupiable level of a dwelling unit, including basements.
  3. In each bedroom where a fuel-burning appliance is located inside (or its attached bathroom)

While the above locations are the minimum required, you can always add them in more locations if you like. Since the risk of death from carbon monoxide poisoning is greatest while you are sleeping, adding additional carbon monoxide alarms in bedrooms is recommended.

Immediate Vicinity
While the code require alarms “outside of each sleeping area in the immediate vicinity of the bedrooms” – the question becomes: what is the immediate vicinity? No definition is given, so you’ll have to use your best judgement. If the sleeping areas are really far apart, or if there is a door that separates the sleeping areas, it’s best to have multiple alarms.

Locations to Avoid
A stand alone carbon monoxide alarm can be a plug-in or battery unit place on the wall or ceiling. The manufacturer will provide instructions for placement, but here are some locations to avoid:

  • When wall mounting, place out of reach of children. Under no circumstances should children be allowed to handle the CO alarm.
  • Do not install in kitchens, garages or furnace rooms that may expose the sensor to substances that could damage or contaminate it.
  • Do not install in areas where the temperature is colder than 40°F or hotter than 100°F.
  • Do not install within 5 ft. of heating or cooking appliances.
  • Do not install near vents, flues, chimneys or any forced/unforced air ventilation openings.
  • Do not install near ceiling fans, doors, windows or areas directly exposed to the weather.
  • Do not install in dead air spaces, such as peaks of vaulted ceilings or gabled roofs, where CO may not reach the sensor in time to provide early warning.
  • Do not obstruct the vents located on the alarm. Do not place the alarm where drapes, furniture or other objects block the flow of air to the vents.

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How many carbon monoxide detectors are required in california

Paul Barraza has been a property inspector since 2007. He is an ASHI Certified Inspector (ACI), a Master CREIA Inspector (MCI), and an ICC Certified California Residential Combination Inspector.

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Where are carbon monoxide detectors required in California?

Effective July 1, 2011, all single family dwelling units require smoke & carbon monoxide detectors throughout the residence. Smoke & carbon monoxide detectors must be installed in accordance with the 2016 California Residential Code (CRC) and will be verified at the permit final inspection.

How many carbon monoxide detectors are needed in a house?

The International Association of Fire Chiefs recommends a carbon monoxide detector on every floor of your home, including the basement. A detector should be located within 10 feet of each bedroom door and there should be one near or over any attached garage. Each detector should be replaced every five to six years.

Are carbon monoxide detectors required by law in California?

Yes. The law requires that CO alarms be installed when fossil fuel appliances are used. Since common areas and hallways leading to the living units can produce CO which could enter the living units by ventilation systems, an alarm would be located within the living unit.

Do I need carbon monoxide detector in every room?

It is important to install CO alarms on every level of your house so all family members can hear the detectors and be alerted to the emergency. You should also have carbon monoxide detectors in every bedroom, outside each sleeping area, and common rooms for extra safety while you and your family are sleeping.