Smoke alarm requirements

Smoke alarm rules say where alarms go (in sleeping rooms, outside sleeping areas and on each story, among other places), that they be interconnected so one sounding sets off all, and how they are powered. They also apply to existing homes when work needing a permit is done: an addition or alteration can trigger new alarms in the existing house.

Expect the inspector to check alarms at the final inspection of a bedroom addition, basement finish or similar project.

The International Residential Code (IRC) is a model code. It is law only where a state or city adopts it, usually with changes, so the wording below shows how the model reads in published government copies, not the rule where you live.

Anne Arundel County, MD

IRC 2021

• 3 feet. Smoke alarms shall not be closer than 3 feet from a bathroom door containing bathtub or shower, unless this would prevent the placement of a smoke alarm required by Section R314.3.¹
• Where more than one smoke alarm is required in accordance with Section R314.3, the alarm devices shall be interconnected.¹

Los Angeles County, CA

Los Angeles County Residential Code

• Smoke alarms shall be installed in the following locations: 1. In each sleeping room. 2. Outside of each separate sleeping area in the immediate vicinity of the bedrooms.²
• 3 feet. Smoke alarms shall be installed not less than 3 feet horizontally from the door or opening of a bathroom that contains a bathtub or shower unless this would prevent placement of a smoke alarm required by this section.²

Yakima County, WA

2012 IRC, Washington State Amended (2013 handout)

• R314.3 Location. Smoke alarms shall be installed in the following locations: 1. In each sleeping room. 2. Outside each separate sleeping area in the immediate vicinity of the bedrooms.³