Smoke Detectors in Existing Dwellings - California

I get asked this question from time to time…

I’m selling my home, why did the home inspector mention a lack of smoke detectors in my home when they weren’t required when it was built?”

• First of all, the Home Inspector was making a common-sense recommendation that is both inexpensive, and in some cases, can alert occupants to a life-threatening situation… fire.

• For most any home that has had an improvement or alteration to the home since about 1992 that would total around $1000, a smoke detector would be required in all sleeping areas.

• It’s also important that Home Inspector’s don’t make requirements, we complete an inspection based on agreed upon standards and note deficiencies where visible. Some items are certainly safety or sometimes, just plain common sense.

Home Inspector’s aren’t Code Inspectors, but I provide the following as an example of a minimum standard.

Smoke Detectors in Existing Single Family Dwellings

**Taken from the 2007 California Building Code **
Additions, alterations, or repairs to group R-3 occupancies. (Section 907. When the valuation of an addition, alteration, or repair to group R-3 occupancy exceeds $1,000 and a permit is required, or when one or more sleeping rooms are added or created in existing group R occupancies, smoke detectors shall be installed in accordance with the following:
Location within dwelling units. (Section 907. In dwelling units, a detector shall be installed in each sleeping room and at a point centrally located in the corridor or area giving access to each separate sleeping area.
When the dwelling unit has more than one story and in dwellings with basements, a detector shall be installed on each story and in the basement. In dwelling units where a story or basement is split into two or more levels, the smoke detector shall be installed on the upper level, except that when the lower level contains a sleeping area, a detector shall be installed on each level. When sleeping rooms are on an upper level, the detector shall be placed at the ceiling of the upper level in close proximity to the stairway. In dwelling units where the ceiling height of a room open to the hallway serving the bedrooms exceeds that of the hallway by 24 inches or more, smoke detectors shall be installed in the hallway and in the adjacent room. Detectors shall sound an alarm audible in all sleeping areas of the dwelling unit in which they are located.
A. Centrally located in the hallway (if no hallway, the area adjacent to the bedroom door) giving access to the bedrooms.
B. In any room that opens into the hallway that has a ceiling level, at any location, 24 inches higher than the lowest ceiling level of the hallway.
C. On the ceiling in close proximity to the stairway.
D. On the lower level ceiling in close proximity to the stairway.
E. In the sleeping rooms
One story house . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A, B, E
Second floor with bedrooms of a two story house . . . . . . . . . . . . . . A, B, C, E
Second floor without bedroom of a two story house . . . . . . . . . . . . C
First floor with bedrooms of a two story house . . . . . . . . . . . . . . . . . A, B, E
First floor without bedrooms of a two story house . . . . . . . . . . . . . . D
Basement with no bedrooms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C
NOTE: Hallway (corridor) - A passageway giving access to rooms, usually enclosed by walls between 3 feet and 5 feet in width.
AUDIBILITY: All detectors must be audible in the bedrooms. Connecting the detectors in series is not required.
NOTE: If any area of a bedroom is more than 30 feet from a detector, an additional detector shall be installed in the bedroom.
POWER SOURCE: Smoke detectors may be solely battery operated when installed in the existing building.
All smoke detectors are to be installed in accordance with the approved manufacturer’s instructions. The above information is not intended to violate any manufacture’s specifications or instructions, but is to be used for interpretation of the Building Code.

Good Post Tim. I get the same question occossionally.

CA State Law REQUIRES smoke detectors in all existing dwellings, so all of my reports incluce this statement.


Hey there guys, Smoke detectors, or lack there of are in the category of anything that effects the " health, habitability or safety" issues that are required under the Calif. Business Code to be called out as deficient. As of July 1, this also included a co2 detector in all sfr’s with fuel burning appliances OR an attached garage.

Actually, the law took effect January 1, 2011. Homeowners were given a 6 month period to comply.

July 1, 2011 is the date when non-compliance would subject homeowners to potential “penalties,” thus, making compliance a “condition of sale.”